Winged cell pump

Abstract

vane pump (1) which has: a housing (2) that defines a pump chamber (20) therein; a rotor (3) which is arranged in the housing (2) and configured to rotate eccentrically about an axis of rotation relative to the housing (2); a plurality of vanes (4) configured to rotate together with the rotor (3) in order to slide on an inner surface of the housing (2); a motor (5) configured to rotate the rotor (3); and a fixing element (6) to which both the motor (5) and the housing (2) are fixed, wherein the housing (2) has an outer side wall surface (25) and a flange (23), the flange (23) projects outwards from the outer side wall surface (25) at an intermediate position between the two ends of the pump chamber (20) in the direction of the rotation axis of the rotor (3), the flange (23) is fixed to the fixing element (6) at a plurality of positions, the fixing element (6) has a linear coefficient of expansion that differs from that of the housing (2), the housing (2) contains a first housing part (21) and a second housing part (22) which are fixed to each other in the direction of the axis of rotation, the first housing part (21) includes a first flange (211) which projects outwards from the outer side wall surface (25), the second housing part (22) includes a second flange (221) that projects outwards from the outer side wall surface (25), the first flange (211) and the second flange (221) are fixed to each other and to the fixing element (6), and at least one of the first flange (211) or the second flange (221) serves as the flange (23) at the intermediate position, the first housing part (21) has an upper plate section (213) which is provided in the direction of the axis of rotation on an upper section of the pump chamber (20), and an outer circumferential wall section (212) which is provided on an outer circumference of the pump chamber (20), the first flange (211) of the outer circumferential wall section (212) serves as the flange (23) at the intermediate position, and the second housing part (22) has a flat plate shape which contains the second flange (221).

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese patent application no. 2019-146174, filed on August 8, 2019. TECHNICAL FIELD

[0002] The present disclosure relates to a vane pump. BACKGROUND

[0003] Patent literature 1 discloses a vane pump comprising a housing, a rotor, and vanes. The housing of the vane pump is fixed directly or indirectly to a motor that rotates the rotor. Depending on the application of the vane pump, it is important to suppress fluctuations in the discharge pressure.

[0004] US 8,549,896 B2 discloses the following: A vane pump has an upper casing, a lower casing, a rotor, and a motor. Points one through four are defined at an outer circumferential end of a lower flat surface of the lower casing. The first point is furthest from an intersection between the axis of a motor shaft and the lower flat surface. An intake port passing through the third point and an outlet port passing through the second point are formed between the upper casing and the lower casing. The fourth point is defined in a region between the third and first points. The lower flat surface is inclined with respect to the axis of the motor shaft such that, among the points at the outer circumferential end, the fourth point is furthest from a motor housing of the motor.

[0005] JP 2011-122541A discloses the following: A point in a position furthest from an intersection between an axis of a shaft and a lower plane of points at the outer circumferential end of the lower plane of a lower case is called the first point, and a point that intersects an imaginary straight line extending from a center point of the lower plane and passing through the first point is rotated 90° in the direction of rotation of a rotor about the center point, is called the second point. A point in a position opposite the second point with the center point between them is called the third point, and a point between the third point and the first point is called the fourth point. In this case, an inlet port passing through the third point and an outlet port passing through the second point are formed between an upper case and the lower case.The lower plane is provided in an inclined state with respect to the axis of the shaft, so that the fourth point of the points at the outer circumferential end is in a position furthest away from a motor housing.

[0006] JP 2000-320 480 A1 discloses the following: A rotary compressor comprises a motor and a rotary compression mechanism that conveys a fluid by increasing and decreasing the volume of a compression chamber in a process of one complete revolution of an eccentric rotor, which is directly coupled to a drive shaft of the motor for the rotary drive. A control element is provided to control the drive of the motor so that, during a single revolution of the eccentric rotor, its rotational speed is changed. LITERATURE ON THE STATE OF TECHNOLOGY PATENT LITERATURE

[0007] Patent literature 1: JP 2012- 241 172 A SUMMARY

[0008] With regard to the requirement to suppress fluctuations in the delivery pressure of the vane pump, the vane pump disclosed in patent literature 1 exhibits the following problems.

[0009] The housing can expand or contract due to temperature changes caused by various factors. If the housing is fixed to a rigid mounting element, such as a motor housing, a pump chamber can deform when the housing expands or contracts.

[0010] Deformation of the pump chamber can lead to uneven changes in the distances between the housing and rotor, as well as between the housing and vanes, depending on how the pump chamber is deformed. As a result, it can be difficult to suppress fluctuations in the delivery pressure of the vane pump.

[0011] One objective of the present disclosure is to provide a vane pump that can suppress temperature-related fluctuations in the delivery pressure. This objective is achieved by the vane pump with the features of claim 1. Further advantageous embodiments and developments are the subject of the subsequent claims.

[0012] According to one aspect of the present disclosure, a vane pump comprises a housing defining a pump chamber therein, a rotor arranged in the housing and configured to rotate eccentrically about an axis of rotation relative to the housing, a plurality of vanes configured to rotate with the rotor to slide on an inner surface of the housing, a motor configured to rotate the rotor, and a fixing element to which both the motor and the housing are attached. The housing has an outer side wall surface and a flange. The flange projects outward from the outer side wall surface at an intermediate position between the two ends of the pump chamber in the direction of the rotor's axis of rotation. The flange is fixed to the fixing element at a plurality of positions.

[0013] In the rotary vane pump described above, the housing has the flange in an intermediate position and is fixed to the flange by a fixing element. Therefore, when the housing expands or contracts due to temperature changes, it is easy to suppress uneven deformation of the housing caused by a difference in the coefficient of linear expansion between the housing and the fixing element. Consequently, the extent of deformation of the pump chamber can be reduced. Therefore, it is possible to suppress fluctuations in the discharge pressure of the rotary vane pump 1 due to temperature changes.

[0014] As described in the preceding aspect, it is possible to provide a vane pump that can suppress fluctuations in delivery pressure due to temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing and other items, features and advantages of the present disclosure will become clearer from the following detailed description, which is given with reference to the accompanying drawings. It shows: Fig. 1 an explanatory cross-sectional view of a vane pump according to the first embodiment along a line II in Fig. 2; Fig. 2 an explanatory top view of a vane pump according to the first embodiment; Fig. 3 a perspective view of a first housing of the first embodiment; Fig. 4 an explanatory cross-sectional view of the vane pump of the first embodiment, illustrating a median plane; Fig. 5 an explanatory cross-sectional view of the vane pump of the first embodiment at a high temperature; Fig. 6 an explanatory cross-sectional view of the vane pump of the first embodiment at a low temperature; Fig. 7 an explanatory cross-sectional view of a vane pump in a comparative example; Fig. 8 an explanatory cross-sectional view of the vane pump of the comparison example at a high temperature; Fig. 9 an explanatory cross-sectional view of the vane pump of the comparison example at a low temperature; Fig. 10 an explanatory cross-sectional view of a vane pump according to the second embodiment; Fig. 11 an explanatory cross-sectional view of the vane pump of the second embodiment at a high temperature; Fig. 12 an explanatory cross-sectional view of the vane pump of the second embodiment at a low temperature; Fig. 13 an explanatory cross-sectional view of a vane pump of the third embodiment; Fig. 14 an explanatory cross-sectional view of a vane pump of the fourth embodiment. Description of the embodiments (First embodiment)

[0016] A vane pump in one embodiment is described with reference to the Fig. 1 to 6.

[0017] As in the present embodiment in Fig. 1 and Fig. As shown in Figure 2, the vane pump 1 contains a housing 2, a rotor 3, several vanes 4, a motor 5 and a fixing element 6.

[0018] The housing 2 defines a pump chamber 20. The rotor 3 is located inside the housing 2 and rotates eccentrically about an axis of rotation relative to the housing 2. Each of the blades 4 rotates together with the rotor 3 and slides on an inner surface of the housing 2. The motor 5 drives the rotor 3. Both the motor 5 and the housing 2 are fixed to the fixing element 6.

[0019] The housing 2 has an outer side wall surface 25 and a flange 23, which is defined as follows. That is, the flange 23 projects from the outer side wall surface 25 in an intermediate position between the two ends of the pump chamber 20 in a rotational axis Z direction of the rotor 3. The flange 23 of the housing 2 is fixed to the fixing element 6 at several positions.

[0020] In the following, the rotation axis direction Z of rotor 3 is also correctly referred to as the axial direction Z. As in Fig. As shown in Figure 1, the flange 23 has a connecting section 231 which is connected to the outer side wall surface 25 of the housing 2. The connecting section 231 is located at an intermediate position, which is closer to a central position of the pump chamber 20 than to either end of the pump chamber 20 in the axial direction X.

[0021] The housing 2, the rotor 3, and the blades 4 are made of plastic. Specifically, the housing 2 is made of a phenolic resin, and the rotor 3 and the blades 4 are made of a PPS resin (i.e., a polyphenylene sulfide resin).

[0022] The motor 5 is arranged axially on one side of the housing 2. The fixing element 6 is arranged axially Z between the motor 5 and the housing 2. The fixing element 6 is made of a material with a coefficient of linear expansion that differs from that of the housing 2. In this embodiment, the fixing element 6 is made of a metallic material such as clad steel.

[0023] The motor 5 and the housing part 2 are then fixed to the fixing element 6. The fact that the motor 5 is fixed to the fixing element 6 means that a stator of the motor 5 is directly or indirectly fixed to the fixing element 6. The in Fig. The depicted state represents a condition in which the housing of the motor 5, to which the stator is attached, is fastened to the fixing element 6. However, the housing of the motor 5 itself can also serve as the fixing element 6. In this case, the housing 2 can be fixed to the housing of the motor 5. For the sake of simplicity, in this description, one side of the fixing element 6, to which the housing 2 is arranged along the axial direction Z, is referred to as the top side, and the opposite side as the bottom side.

[0024] As in Fig. As shown in Figure 1, the housing 2 comprises a first housing part 21 and a second housing part 22. The first housing part 21 and the second housing part 22 are fixed to each other in the axial direction Z. The first housing part 21 has a first flange 211. The first flange 211 projects outwards from the outer side wall surface 25 of the housing part 2. The second housing part 22 has a second flange 221. The second flange 221 projects outwards from the outer side wall surface 25 of the housing part 2. The first housing part 21 and the second housing part 22 are fixed to each other and to the fixing element 6 at the first flange 211 and at the second flange 221. At least the first flange 211 or the second flange 221 is the flange 23 at the intermediate position.

[0025] In this embodiment, the first flange 211 is the flange 23 at the intermediate position. Conversely, in this embodiment, the second flange 221 is not the flange 23 at the intermediate position.

[0026] The second housing part 22 has a substantially flat plate shape. On the other hand, the first housing part 21, as in Fig. Figures 1 to 3 show an outer circumferential wall section 212 and an upper plate section 213. The outer circumferential wall section 212 has a substantially cylindrical shape with an inner circumferential surface substantially parallel to the axial direction Z. The upper plate section 213 has a substantially circular, flat plate shape perpendicular to the axial direction Z. The upper plate section 213 is connected to the upper end of the outer circumferential wall section 212. That is, the upper plate section 213 covers the upper section of the pump chamber 20.

[0027] The outer surface of the outer circumferential wall section 212 forms the outer side wall surface 25 of the housing 2. That is, the first flange 211 (i.e., the flange 23 at the intermediate position) projects outwards from the outer circumferential wall section 212. Furthermore, as shown in Fig. Figure 1 shows the lower end of the outer circumferential wall section 212 in contact with the upper surface of the second housing part 22. The lower end of the outer circumferential wall section 212 fully contacts the upper surface of the second housing part 22 in the circumferential direction. This defines the pump chamber 20 between the first housing part 21 and the second housing part 22.

[0028] Here is how in Fig. Figure 4 shows a median plane F defined as a plane perpendicular to the axis of rotation and passing axially through a central position of the pump chamber 20. At least a portion of the connecting section 231 of the flange 23, which is connected to the outer side wall surface 25 of the housing 2, is located on each side of the median plane F. That is, part of the connecting section 231 is located on the top of the median plane F and the other part of the connecting section 231 is located on the bottom of the median plane F.

[0029] In this embodiment, the joint section 231 of the first flange 211, i.e., of the flange 23 at the intermediate position, extends over the median plane F. In other words, the median plane F passes through the joint section 231 of the flange 23 at the intermediate position.

[0030] As in Fig. As shown in Figure 2, in this embodiment the first flange 211 and the second flange 221 are formed continuously over the entire circumference of the outer side wall surface 25 of the housing 2. As shown in Fig. 1 and Fig. As shown in Figure 3, the first flange 211 includes a lateral projection 214 extending outwards from the connecting section 231, and leg sections 215 extending downwards from the lateral projection 214 in the axial direction Z. There are three leg sections 215.

[0031] The first flange 211 and the second flange 221 overlap each other in the axial direction Z and are in contact with each other at the three leg sections 215. The first flange 211 and the second flange 221 are fixed to the fixing element 6 at several contact points. That is, the contact points between the first flange 211 and the second flange 221 are fixed to the fixing element 6 by screws 11. The number of fixing points, that is, the number of sections of the legs 215, is three in this embodiment, but is not limited to this and can be four or more. If the pump chamber 20 can be defined in a suitable manner, the number of fixing points can also be two.

[0032] Each of the screws 11 is inserted into an insertion hole 216 of the first flange 211 and an insertion hole 226 of the second flange 221 and screwed into an internally threaded screw 66 of the fixing element 6. This fixes the first flange 211 and the second flange 221 to the fixing element 6 in the axial direction Z, and the first flange 211 and the second flange 221 are fixed to each other. Although not shown, the screw 11 can pass through the fixing element 6 and be screwed into a nut located on a bottom surface of the fixing element 6.

[0033] Furthermore, in the state prior to fixing the first housing part 21 to the second housing part 22 or the like, the lower ends of the leg sections 215 are arranged to project slightly towards the lower end of the outer circumferential wall section 212. This allows the lower end of the outer circumferential wall section 212 to be reliably pressed against the upper surface of the second housing part 22.

[0034] In the vane pump 1 of this embodiment, the rotor 3 is controlled so that it rotates at a constant speed. That is, the motor 5, which drives the rotor 3, is controlled so that it rotates at a constant speed.

[0035] If the drive power of the vane pump 1 is constant, the rotational speed of the vane pump 1 can fluctuate due to various factors such as variations in frictional resistance. On the other hand, depending on the application of the vane pump 1, it may be necessary to avoid fluctuations in rotational speed. Therefore, a constant speed control is implemented in such a housing component to maintain a constant rotational speed.

[0036] The vane pump 1 of this embodiment is used, for example, in a device for processing volatile fuel, which is equipped with a leak detection unit for volatile fuel. That is, the vane pump 1 is used, for example, as a decompression pump to relieve the pressure of a diagnostic system containing a canister. The leak detection unit is configured, for example, to diagnose a leak in the diagnostic system based on a pressure change when the pressure in the system is reduced by the vane pump 1.

[0037] The present embodiment provides the following functions and advantages.

[0038] In the vane pump 1, the housing 2 has the flange 23 in an intermediate position, and the flange 23 is fixed to the fixing element 6. As a result, uneven deformation of the housing due to a difference in the coefficient of linear expansion between the housing 2 and the fixing element 6 can be easily suppressed, even if the housing 2 expands or contracts due to a temperature change. That is, even if the temperature of the housing 2 changes due to the influence of heat generated by the sliding of the rotor 3, heat transfer from the motor 5, or a change in the ambient temperature, uneven deformation of the housing 2 can be easily suppressed. Consequently, the extent of deformation of the pump chamber 20 can be suppressed. Therefore, it is possible to suppress fluctuations in the discharge pressure of the vane pump 1 due to temperature changes.

[0039] The above functions and advantages are compared to a vane pump 9 of a Fig. The comparative example shown in sections 7 to 9 is described.

[0040] In the case of the vane pump 9 of the in Fig. In the comparative example 7, the first flange 211 protrudes from the housing 2 at the lower end of the pump chamber 20. That is, the lower end surface of the first flange 211 lies in the same plane as the lower end of the pump chamber 20. Furthermore, the second flange 221 is located on the underside of the first flange 211. Therefore, in the vane pump 9 of the comparative example, neither the first flange 211 nor the second flange 221 protrudes axially Z at the intermediate position between the two ends of the pump chamber 20. That is, neither the first flange 211 nor the second flange 221 corresponds to the aforementioned "flange at the intermediate position".

[0041] The following problems arise with the vane pump 9, which has such a configuration. That is, if the housing 2 is fixed to the fixed fixing element 6, which has a relatively small coefficient of linear expansion, the housing 2 can deform unevenly due to the difference in the coefficient of linear expansion between the housing 2 and the fixing element 6. For example, the housing 2 expands more than the fixing element 6 at high temperatures.

[0042] At this point, as in Fig. Figure 8 shows a section of the housing 2 near the first flange 211 and the second flange 221, which are fixed by the screws 11, restricted in deformation by the fixing element 6.

[0043] On the other hand, a section of the housing 2 that is away from the first flange 211 and the second flange 221 may deform.

[0044] In this housing section, the dimensional change of the pump chamber 20 varies in the axial direction Z, and uneven deformation of the pump chamber 20 can occur. The clearance between the inner surface of the pump chamber 20 and the rotor 3, as well as between the inner surface and the vanes 4, can then fluctuate significantly. As a result, fluctuations in the discharge pressure of the vane pump 1 can occur.

[0045] Furthermore, the housing 2 contracts more at low temperatures than the fixing element 6. Therefore, as in Fig. As shown in Figure 9, the pump chamber 20 is more compressed in a section located further away from the first flange 211 and the second flange 221, which are fixed to the fixing element 6, than in a section located closer to the first flange 211 and the second flange 221. Consequently, uneven deformation of the pump chamber 20 is likely to occur at high temperature. Therefore, the discharge pressure of the vane pump 1 is also likely to fluctuate.

[0046] In the present embodiment of the vane pump 1, as described in Fig. As shown in Figure 4, the housing 2, however, has the flange 23 in an intermediate position. This means that the difference in distance between the flange 23, fixed to the fixing element 6, and each of the positions of the housing 2 is small. Therefore, even if the housing 2 expands or contracts with temperature changes, the uneven deformation of the pump chamber 20 can be suppressed.

[0047] That is, as for example in Fig. As shown in Figure 5, even if the housing 2 expands and deforms slightly at a high temperature, the pump chamber 20 is less likely to deform unevenly. Therefore, the distance between the inner surface of the pump chamber 20 and the rotor 3, as well as the distance between the inner surface and the individual blades 4, fluctuate less. Consequently, fluctuations in the pump discharge pressure can be suppressed.

[0048] Even in the case where housing 2 contracts and deforms slightly at a low temperature, as in Fig. As shown in Figure 6, it is less likely that the pump chamber 20 will deform unevenly. Therefore, as described above, fluctuations in the pump delivery pressure can be suppressed.

[0049] The first housing part 21 and the second housing part 22, which form the housing 2, are fixed to each other and to the fixing element 6 at the first flange 211 and the second flange 221. The first flange 211 is the flange 23 in the intermediate position. Thus, the assembly of the housing 2 and its fixing to the fixing element 6 are carried out at the same positions. This enables an improvement in productivity and a simplification of the vane pump 1.

[0050] Furthermore, at least part of the connecting section 231 of the flange 23 is located at the intermediate position on each side of the center plane F. This allows the uneven deformation of the pump chamber 20 due to temperature changes to be suppressed more effectively.

[0051] Furthermore, the vane pump 1 is controlled to rotate at a constant speed, thus ensuring a constant rotational speed of the rotor 3. This suppresses fluctuations in the pump's discharge pressure. In the vane pump 1, which operates under this control, the uneven deformation of the pump chamber 20 due to temperature changes is suppressed. This effectively reduces fluctuations in the pump's discharge pressure.

[0052] Furthermore, as described above, when using the vane pump 1 in the fuel processing unit provided with the leak detection unit, it is important to keep the pump outlet pressure, i.e., the vacuum, constant. If the pump outlet pressure fluctuates, highly accurate leak diagnosis becomes difficult. Therefore, the constant rotation control described above is implemented. This allows the pump outlet pressure to be kept constant and improves the accuracy of the leak diagnosis. However, even if the rotational speed of the rotor 3 is kept constant, the pump delivery pressure can be affected by deformation of the pump chamber 2 together with deformation of the housing 2.Therefore, in the case of the vane pump 1, which performs constant rotation control, a configuration in which the flange 23 is provided at the intermediate position, as in the present embodiment, is preferable from the point of view that the pump discharge pressure can be kept more constant.

[0053] As described above in the present embodiment, it is possible to provide a vane pump that can suppress temperature-related fluctuations in the delivery pressure. (Second embodiment)

[0054] At the in Fig. In the embodiment shown in Figure 10, both the first flange 211 of the first housing part 21 and the second flange 221 of the second housing part 22 are flanged at the intermediate position 23.

[0055] In the vane pump 1 of the present embodiment, the second housing part 22 also has an outer circumferential wall section 222. That is, the second housing part 22 has an outer circumferential wall section 222, which has a substantially cylindrical shape, and a lower plate section 223, which is connected to the lower end of the outer circumferential wall section 222. The second flange 221 projects outwards from the upper end of the outer circumferential wall section 222. Furthermore, in the first housing part 21, the first flange 211 projects outwards from the lower end of the outer circumferential wall section 212.

[0056] Furthermore, the fixing element 6 has a contact section 61 that is in contact with the lower surface of the second flange 221. The contact section 61 of the fixing element 6 is located forward in a section of the fixing element 6 that is situated within the contact section 61.

[0057] In this embodiment, as described above, both the first flange 211 and the second flange 221 form the flange 23 at the intermediate position. Furthermore, at least a part of the connecting section 231 of the flange 23 is located at the intermediate position on each side of the central plane F.

[0058] Other sections are the same as in the first embodiment.

[0059] The reference numerals used in the second and subsequent embodiments, which are the same reference numerals as those used in the embodiments described above, denote the same components as in the preceding embodiments, unless otherwise specified.

[0060] In this embodiment as well, it is as in Fig. 11 and Fig. As shown in Figure 12, it is possible to suppress uneven deformation of the pump chamber 20 due to a temperature change and to suppress fluctuations in the pump delivery pressure.

[0061] That is, as for example in Fig. As shown in Figure 11, even if the housing 2 expands and deforms slightly at a high temperature, the pump chamber 20 is less likely to deform unevenly. Therefore, the distance between the inner surface of the pump chamber 20 and the rotor 3, as well as the distance between the inner surface and the individual blades 4, fluctuate less. Consequently, fluctuations in the pump discharge pressure can be suppressed.

[0062] Even in the case that housing 2 contracts and deforms slightly at a low temperature, as in Fig. As shown in Figure 12, it is less likely that the pump chamber 20 will deform unevenly. Therefore, as described above, fluctuations in the pump delivery pressure can be suppressed.

[0063] Furthermore, this embodiment has the same functions and advantages as the first embodiment. (Third embodiment)

[0064] At this in Fig. In the embodiment shown in Figure 13, a spacer 12 is arranged between the first flange 211 and the second flange 221.

[0065] The screws 11 pass through the first flange 211, the spacer 12, and the second flange 221 and are fixed to the fixing element 6. The spacer 12 can, for example, be made of the same plastic as the first housing part 21 and the second housing part 22.

[0066] The other configuration is the same as the first embodiment and has the same functions and advantages.

[0067] As in this embodiment, the first flange 211 and the second flange 221 can be configured so that they are not in direct contact with each other. (Fourth embodiment)

[0068] In this embodiment, as described in Fig. As shown in Figure 14, the spacer 12 is inserted between the first flange 211 and the second flange 221.

[0069] In the present embodiment, however, as in the second embodiment, both the first flange 211 and the second flange 221 serve as flange 23 at the intermediate position, and the spacer 12 is inserted between them. Furthermore, the spacer 12 is annular and extends fully in the circumferential direction Z of the pump chamber 20.

[0070] In this embodiment, the median plane F passes through the spacer 12. The first flange 211, which serves as flange 23 at the intermediate position, and the second flange 221, which also serves as flange 23 at the intermediate position, are each arranged on opposite sides of the median plane F.

[0071] Furthermore, this embodiment has the same functions and advantages as the first embodiment.

[0072] The present disclosure is not limited to the respective embodiments described above, and various modifications may be adopted within the scope of the present disclosure without deviating from the basic idea of ​​the disclosure.

[0073] Although the present disclosure has been described according to the embodiments, it is understood that the present disclosure is not limited to such embodiments or constructions. The present disclosure includes various modifications and variations within the scope of equivalents. Furthermore, while the various elements are shown in different combinations and configurations, which are exemplary, other combinations and configurations, including more, fewer, or only a single element, are also within the scope of the appended claims.

Claims

[1] Vane pump (1) comprising: a housing (2) defining a pump chamber (20) therein; a rotor (3) arranged in the housing (2) and configured to rotate eccentrically about a rotation axis relative to the housing (2); a plurality of vanes (4) configured to rotate together with the rotor (3) to slide on an inner surface of the housing (2); a motor (5) configured to rotate the rotor (3); and a fixing element (6) to which both the motor (5) and the housing (2) are fixed, wherein the housing (2) has an outer side wall surface (25) and a flange (23), the flange (23) projects outwards from the outer side wall surface (25) at an intermediate position between the two ends of the pump chamber (20) in the direction of the rotation axis of the rotor (3), the flange (23) is fixed to the fixing element (6) at a plurality of positions, the fixing element (6) has a linear expansion coefficient which differs from that of the housing (2), the housing (2) contains a first housing part (21) and a second housing part (22) which are fixed to one another in the direction of the axis of rotation, the first housing part (21) includes a first flange (211) projecting outwardly from the outer side wall surface (25), the second housing part (22) includes a second flange (221) projecting outwardly from the outer side wall surface (25), the first flange (211) and the second flange (221) are fixed to each other and to the fixing element (6), and at least one of the first flange (211) or the second flange (221) serves as the flange (23) at the intermediate position, the first housing part (21) has an upper plate portion (213) provided in the direction of the rotation axis at an upper portion of the pump chamber (20), and an outer circumferential wall portion (212) provided at an outer periphery of the pump chamber (20), the first flange (211) of the outer circumferential wall portion (212) serves as the flange (23) at the intermediate position, and the second housing part (22) has a flat plate shape which contains the second flange (221). [2] Vane pump (1) according to claim 1, wherein a center plane (F) is defined as a plane perpendicular to the axis of rotation and passing through a center position of the pump chamber in the direction of the axis of rotation, the flange (23) has a connecting portion (231) connected to the outer side wall surface (25) of the housing (2), and the central plane (F) passes through the connecting section (231). [3] Vane pump (1) according to claim 1 or 2, wherein the rotor (3) is controlled to rotate at a constant speed.

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