JPWO2014147914A1 - Vane pump - Google Patents

Abstract

The vane pump includes a rotor (11) in which slit grooves (12) are radially formed on the outer periphery in a pump housing (2), a vane (21) accommodated in each slit groove (12), and each vane ( 21) An end section having a cam ring (31) having a cam surface (32) with which the front end thereof is in sliding contact and an axial end of the rotor (11) and having a suction port (42) and a discharge port (43). Members (2A, 2B). The rotor (11) has a recess (15) formed between the slit grooves (12) on the outer peripheral surface (14) thereof, and the inner wall surface (42a) of the suction port (42) is connected to the bottom surface (15a) of the recess (15). ) And the position closer to the pump shaft center (1c).

Description

  The present invention relates to a vane pump used as an oil pump.

  In a vane pump used as an oil pump, by providing a recess (groove) on the outer periphery of the rotor, it is possible to secure the area for sucking oil into the pump chamber while securing the stroke of the vane. A technique has been developed in which the pressure drop in the pump chamber is suppressed and the flow rate drop due to the occurrence of cavitation is suppressed (see, for example, Patent Document 1).

  By the way, it has been found that by providing a concave portion on the outer periphery of the rotor, the occurrence of cavitation is suppressed, and even if the decrease in the oil flow rate due to the occurrence of cavitation is suppressed, the desired pump performance may not be obtained.

  The inventor has sought this cause. Hereinafter, a description will be given with reference to FIG. First, a vane pump in which a recess is provided on the outer periphery of the rotor will be described. As shown in FIG. 5, a plurality of slit grooves 112 are radially formed in the rotor 111, and vanes 121 are accommodated in the respective slit grooves 112 so as to be able to appear and disappear. The rotor 111 is disposed inside a cam ring 131 having a cam surface 132 formed on the inner periphery, and the tip of each vane 121 protruding outward from the rotor 111 is in sliding contact with the cam surface 132 on the inner periphery of the cam ring 131.

  A back pressure hole 113 for applying a biasing force for pressing the vane 121 against the cam surface 132 of the cam ring 131 is formed at the base of each slit groove 112. The back pressure holes 113 communicate with each other in an annular shape and are not shown in the drawing. Oil is supplied from the road. The oil pressure in the back pressure hole 113 acts on the base of the vane 121 and presses the vane 121 against the cam surface 132 of the cam ring 131.

  The rotor 111 and the cam ring 131 are installed in a pump housing (not shown), and a space between the outer peripheral surface 114 of the rotor 111 and the cam surface 132 on the inner periphery of the cam ring 131 is partitioned by the wall surfaces of the adjacent vanes 121 and 121. 141 is formed. Further, both end directions of the pump chamber 141 (both sides in the extending direction of the rotating shaft of the rotor 111) are respectively partitioned by a cover member of the pump housing or an end partition member such as an end plate built in the pump housing.

  A suction port (not shown) is provided at a location where the volume of the pump chamber 141 is increased by the cam surface 132, and a discharge port (not shown) is provided at a location where the volume of the pump chamber 141 is reduced by the cam surface 132. Oil is sucked into each pump chamber 141 from the suction port, and oil is discharged from the discharge port. A recess 115 is formed on the outer peripheral surface 114 of the rotor 111 in the axial direction of the rotor 111 except for the vicinity of the slit groove 112.

  Here, in order to suppress the occurrence of cavitation and improve the suction performance of the pump, it is effective to deepen the recess 115 and increase the suction area. However, the present inventor It has been found that it depends on the relationship between the port and the recess.

  In other words, in order to improve the suction performance, even if the bottom surface of the recess is brought closer to the pump shaft center (that is, the recess is deeper) in order to increase the suction area, the pump shaft side of the suction port may be affected by manufacturing errors. When the wall surface is away from or close to the pump shaft center with respect to the bottom surface of the recess, the flow path is a space through which oil flows between the suction port side and the pump chamber side. The uneven state is reversed. As described above, when the uneven state is reversed between the suction port side and the pump chamber side with respect to the flow path, the pressure loss of the oil flowing there changes greatly, and the suction performance is greatly affected. With such a mechanism, it was clarified that the suction performance of the pump changes greatly and the performance of each pump varies.

  The present invention was devised in view of such problems, and it is possible to stabilize the performance of each pump while securing the oil suction area and suppressing the pressure drop in the pump chamber to suppress the flow rate drop due to the occurrence of cavitation. An object of the present invention is to provide a vane pump that can be used.

Japanese Utility Model Publication No. 61-181888

  The present invention was created to achieve the above object, and the vane pump of the present invention has the following gist configuration.

  (1) That is, the vane pump of the present invention includes a rotor in which a plurality of slit grooves are radially formed on an outer peripheral surface in a pump housing, a vane accommodated in each slit groove so as to be able to appear and retract, A cam ring provided on the inner periphery with a cam surface arranged on the outer periphery and in which the tip of each vane slidably contacts, and end partition members (for example, a pump cover or a side plate) respectively provided at both axial ends of the rotor. Then, each pump chamber is formed to be surrounded by the outer peripheral surface of the rotor, the cam surface, the wall surface of the adjacent vane and the end partition member, and oil is sucked into the pump chamber by the end partition member. A vane pump having a suction port for discharging and a discharge port for discharging oil from the pump chamber, wherein the gap between the slit grooves constituting the inner periphery of each pump chamber On the outer peripheral surface of the rotor, a recess is formed in which a central portion between both end portions is recessed rather than a circumference connecting the tip ends of the slit grooves, and a wall surface on the pump shaft center side of the suction port The inner wall surface of the suction port is set at a position closer to the pump shaft center than the bottom surface of the recess. The position where the inner wall surface of the suction port is closer to the pump axis than the bottom surface is that the distance from the pump shaft center of the inner wall surface of the suction port is shorter than the distance from the pump shaft center of the bottom surface, It means that the inner wall surface of the suction port is closer to the pump shaft center than the bottom surface.

  (2) The maximum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance is set equal to the maximum value of the distance from the pump shaft center of the inner wall surface of the suction port including the manufacturing tolerance. It is preferable that

  (3) Moreover, it is preferable that one manufacturing tolerance is set relatively small among the manufacturing tolerance of the bottom face of the said recessed part, and the manufacturing tolerance of the said suction port inner wall surface. In this case, it is preferable that the manufacturing tolerance of the bottom surface of the recess is set smaller than the manufacturing tolerance of the inner wall surface of the suction port.

  (4) Alternatively, the minimum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance is larger than the maximum value of the distance from the pump shaft center of the inner wall surface of the suction port including the manufacturing tolerance. It is also preferable that it is set.

  (5) Preferably, the rotor is formed by sintering, and the end section member is formed by sand casting.

  (1) According to the vane pump of the present invention, the distance between both ends of the rotor chamber is larger than the circumference connecting the tip of the end where the slit groove is formed on the outer peripheral surface of the rotor between the slit grooves constituting the inner periphery of each pump chamber. Since the concave portion in which the central portion of the suction port is recessed is formed, and the suction port inner wall surface, which is the wall surface on the pump shaft center side of the suction port, is set at a position closer to the pump shaft center than the bottom surface of the recess portion, the pump Variations in performance can be suppressed.

  It has been found that not only the shape on the rotor side but also the shape on the suction port side has a great influence on the oil suction performance that affects the performance of the pump. In the present invention, paying attention to this point, the wall surface on the pump shaft center side of the suction port is made closer to the pump shaft center than the bottom surface of the recess. Due to the position setting of the wall surface of the suction port, there is a manufacturing error, and even if the wall surface on the pump shaft side of the suction port is separated from the pump shaft center, the bottom surface of the recess is on the pump shaft side. Even when approaching, the wall on the pump shaft center side of the suction port is prevented from projecting toward the flow path through which the oil flows, and the wall surface on the pump shaft center side of the suction port and the bottom surface of the recess. It is suppressed that the unevenness | corrugation relationship differs for every pump.

  For this reason, if the state in which the bottom surface of the concave portion protrudes from the wall surface on the pump shaft center side to the flow path side in advance in the design, a pump having a desired oil suction property can be obtained. Variations in performance can be suppressed.

  (2) Further, the maximum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance is set equal to the maximum value of the distance from the pump shaft center of the inner wall of the suction port including the manufacturing tolerance. Even in the most severe conditions where each distance is the maximum value and the suction area is minimum, the inner wall surface of the suction port does not protrude beyond the bottom surface of the recess, resulting in a step in the flow path through which the oil flows. It is possible to suppress the deterioration of the sucking property by eliminating the loss due to.

  (3) Also, in order to suppress the unevenness relationship between the wall surface on the pump shaft side of the suction port and the bottom surface of the recess from being replaced for each pump, when manufacturing tolerance itself, which is a manufacturing error, is reduced, By making only the manufacturing tolerance relatively small, it is possible to suppress an increase in component manufacturing cost. In this case, the bottom of the concave portion on the rotor side is suitable for reducing the manufacturing tolerance.

  In the case of a vane pump, it is necessary to suppress a pressure drop in the pump chamber to suppress a flow rate decrease due to the occurrence of cavitation. To suppress this flow rate decrease, it is effective to secure an oil suction area. By forming a recess in which the central part between both ends is recessed rather than the circumference connecting the tips of the ends where the slit grooves are formed, the oil suction area can be secured. In particular, in order to secure the oil suction area, the closer the bottom surface of the recess is to the pump shaft center, the more effective. On the other hand, when the recess is formed in the pump chamber, it becomes impossible to make the volume of the pump chamber near the discharge port zero, and oil remains in the pump chamber even after the discharge process, so that the oil remains in the recess. . Oil contains air, but the oil rotated by the rotor is separated into a part containing a lot of air and a part not containing it by centrifugal force, and the oil containing a lot of air remains in a recess near the center of rotation. . As a result, the air contained in the oil accumulated in the recesses expands and precipitates on the suction side, so that the amount of oil that is sucked decreases and the discharge amount of oil decreases. In particular, when the recessed portion becomes deeper and the amount of accumulated oil increases, the air also increases accordingly, causing discharge flow rate pulsation and discharge pressure pulsation, resulting in malfunction of the flow rate control valve in the oil pump and oil pump noise.

  As described above, since the recess of the rotor causes deterioration of the suckability even if it is too deep or too shallow, the manufacturing tolerance on the rotor side is reduced to suppress the deterioration of the suckability. On the other hand, since the end section member does not require processing accuracy as much as the rotor, the manufacturing tolerance is increased. That is, the manufacturing tolerance of the bottom surface of the recess processed into the rotor is set to be smaller than the manufacturing tolerance of the inner wall surface of the suction port provided in the end section member. Thereby, generation | occurrence | production of the discharge flow rate pulsation and discharge pressure pulsation by the air in the oil which remains in a recessed part can be suppressed, suppressing the increase in manufacturing cost, and the performance of a vane pump can be improved.

  (4) Further, the minimum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance is set larger than the maximum value of the distance from the pump shaft center of the inner wall surface of the suction port including the manufacturing tolerance. Since the suction port inner wall surface does not protrude from the bottom surface of the recess with respect to the suction area determined by the recess, it is possible to eliminate the effect of reversal of the uneven state on the suction port side and the pump chamber side, It becomes easy to secure the performance required for the vane pump for each pump.

  (5) Further, if the rotor is sintered and the end section member is formed by sand casting, the manufacturing tolerance of the rotor can be reduced, and the manufacturing tolerance of the end section member is increased, but the manufacturing cost is increased. Can be suppressed.

It is a longitudinal cross-sectional view which shows the structure of the vane pump concerning one Embodiment of this invention, and is AA arrow sectional drawing of FIG. It is a principal part cross-sectional view which shows the structure of the vane pump concerning one Embodiment of this invention. It is a figure explaining the structure of the vane pump concerning one Embodiment of this invention, (a) is a perspective view of the rotor, (b) is a cross-sectional view of the rotor half part. The positional relationship of the pump shaft center reference between the bottom surface of the concave portion of the vane pump and the inner wall surface of the suction port according to the embodiment of the present invention is the same as that of the rotor formed on the bottom surface of the concave portion and the end partition member formed on the inner wall surface of the suction port. It is a figure shown in relation to each manufacturing tolerance. It is a principal part cross-sectional view of the vane pump explaining the subject of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show the structure of a vane pump according to an embodiment of the present invention. This vane pump is used as an oil pump.

[Vane pump structure]
First, the structure of the vane pump according to this embodiment will be described. As shown in FIGS. 1 and 2, the vane pump is provided with a rotor 11 and a cam ring 31 in a pump housing 2. The rotor 11 is coupled so as to rotate integrally with a rotary shaft 1 provided at the center of the pump housing 2. The rotating shaft 1 is connected to an engine (internal combustion engine) or a motor (electric motor) (not shown) directly or indirectly and is driven to rotate.

  A plurality of slit grooves 12 are radially formed in the rotor 11 as viewed in a cross section as shown in FIG. 2, and vanes 21 are accommodated in the respective slit grooves 12 so as to be able to appear and disappear. The cam ring 31 is disposed on the outer periphery of the rotor 11, and the cam surface is formed on the inner periphery of the cam ring 31 by a curved surface whose distance changes with respect to the axis (rotation center, pump axis) 1 c of the rotation shaft 1. 32 is formed. The tip of each vane 21 is in sliding contact with the cam surface 32 on the inner periphery of the cam ring 31. In the present embodiment, the cam surface 32 is provided at two locations on the entire circumference with a 180 ° phase change, and a location closest to the rotation center and a location farthest from the rotation center.

  In the present embodiment, back pressure holes 13 are formed at the base ends of the slit grooves 12 (ends on the axis 1c side of the rotating shaft 1), and the back pressure holes 13 are connected to each other by a communication path 13A. . A part of oil (working oil) discharged from a discharge port 43 described later is supplied to each back pressure hole 13 through the communication passage 13A, and each oil pressure (back pressure) supplied to the back pressure hole 13 is changed to each of the back pressure holes 13. The vane 21 in the slit groove 12 is urged toward the outer cam surface 32, and the tip of each vane 21 is in sliding contact with the cam surface 32 by this urging force.

  Further, one end (lower end in FIG. 1) of the shaft of the rotor 11 is extended at the other end in the axial direction of the rotor 11 by a sand plate (end section member) 2A interposed inside one end of the pump housing 2. (Upper end in FIG. 1) is closed except for the suction port 42 and the discharge port 43 by a pump cover (end section member) 2 </ b> B coupled to the opening at the other end of the pump housing 2.

  Thus, the pump chamber 41 is formed by being surrounded and partitioned by the outer peripheral surface 14 of the rotor 11, the cam surface 32 of the cam ring 31, the wall surface of the adjacent vane 21, the end plate 2 </ b> A, and the rotor end closed portion 2 </ b> B. A suction port 42 for sucking oil into the pump chamber 41 and a discharge port 43 for discharging oil from the pump chamber 41 are provided. The suction port 42 and the discharge port 43 are provided at two locations on the entire circumference, changing the phase by 180 degrees corresponding to the shape of the cam surface 32.

  The suction port 42 is provided at a location where the volume of the pump chamber 41 increases with the rotation of the rotor 11 due to the shape of the cam surface 32, and the discharge port 43 is pumped with the rotation of the rotor 11 due to the shape of the cam surface 32. The chamber 41 is provided at a location where the volume is reduced. In this embodiment, the suction ports 42 are provided at both ends (upper and lower ends in FIG. 1) of the shaft of the rotor 11, and the discharge port 43 is one end (lower end of FIG. 1) in the direction of extension of the shaft of the rotor 11. ). In FIG. 2, the arrangement positions of the suction port 42 and the discharge port 43 are schematically shown by a two-dot chain line, and the port shape is not strictly specified.

  The suction ports 42 at both ends communicate with each other through a communication passage 42 b, and oil is introduced into the suction port 42 from a tank or the like (not shown) through suction passages 44, 44 a, 44 b due to the rotation of the rotor 11. The oil is discharged, and the oil discharged from one discharge port 43 merges with the other discharge port 43 through the discharge flow path 45a, and from the other discharge port 43 to the oil supply portion (not shown) through the discharge flow path 45b. Supplied.

  In the present embodiment, a characteristic structure is provided on the outer peripheral surface 14 of the rotor 11 that forms the inner peripheral surface of the pump chamber 41. That is, as shown in FIG. 3, the outer peripheral surface 14 of the rotor 11 is provided with a protruding edge 16 that protrudes outward (circumferentially outward) along both edges of the slit groove 12. Between the two raised edges 16, 16 facing each other, a recess 15 that is recessed from the two raised edges 16, 16 is formed.

  By forming the recess 15, the oil suction area in the suction port 42 is increased without changing the outer diameter of the rotor 11, the inner diameter of the cam ring 31, and the radial depth of the slit groove 12. While securing the stroke, it is possible to improve the oil suction performance during high-speed operation. Thereby, generation | occurrence | production of the cavitation at the time of oil suction can be suppressed, and the rotation sound and discharge pulsation of a pump can be made small.

As shown in FIG. 1, the suction port inner wall surface 42 a, which is the wall surface of the suction port 42 on the pump shaft center 1 c side, is set at a position closer to the pump shaft center 1 c than the bottom surface 15 a of the recess 15. In other words, the distance (hereinafter also referred to as the suction port inner wall surface distance) r ₂ of the suction port inner wall surface 42 a from the pump shaft center 1 c is referred to as the distance (hereinafter referred to as the recess bottom surface) of the bottom surface 15 a of the recess 15. distance also called) is set to less than r _1. However, this setting is a setting of the median value (reference value) of each distance without considering manufacturing tolerances.

Here, the manufacturing tolerance will be considered. The manufacturing tolerance ± t ₁ (where t ₁ > 0) of the rotor 11 where the recess 15 is formed is equal to the manufacturing tolerance ± t _{2 of the} end section member (sand plate 2A or pump cover 2B) where the suction port 42 is formed. (However, t ₂ > 0) is set smaller than the maximum value r _1MAX of the distance from the pump shaft center 1c of the bottom surface 15a of the recess 15 including the manufacturing tolerance ± t ₁ (hereinafter also referred to as the recess bottom surface distance). The maximum value r _2MAX of the distance from the pump shaft center 1c of the suction port inner wall surface 42a including the manufacturing tolerance ± t ₂ (hereinafter also referred to as the suction port inner wall surface distance) is set equal. Note that the following manufacturing tolerances t ₁ and t ₂ indicate the manufacturing tolerances ± t ₁ and ± t ₂ by paying attention to their magnitudes (absolute values).

That is, assuming that the median value (reference value) of the recess bottom surface distance is r ₁ and the median value (reference value) of the suction port inner wall surface distance is r ₂ , the maximum value r of the recess bottom surface distance including the manufacturing tolerance ± t ₁ The relationship between _1MAX (= r ₁ + t ₁ ) and the maximum value r _2MAX (= r ₂ + t ₂ ) of the inner wall surface distance including the manufacturing tolerance ± t ₂ is expressed by the following equations (1) and (1 ′). It becomes. Further, the manufacturing tolerance t _{1 of the} rotor 11 in which the recess 15 is formed and the manufacturing tolerance t _{2 of the} end section members 2A and 2B in which the suction port 42 is formed have the relationship of the following equation (2).

Therefore, the median value r ₁ of the concave bottom surface distance, a median r ₂ of the suction port in the wall distance, a relationship of the following equation (3).
r _1MAX = r _2MAX (1)
∴r ₁ + t ₁ = r ₂ + t ₂ (1 ′)
t ₁ <t ₂ (2)
r ₁ > r ₂ (3)

Incidentally, FIG. 4 is a median r ₁ of the concave bottom surface distance, a median value r ₂ of the suction port in the wall distance, the manufacturing tolerances ± t ₁ of the rotor 11, the end sections member 2A, 2B manufacturing tolerances ± t ₂ shows the relationship between the maximum value r _1MAX of the recess bottom surface distance and the maximum value r _2MAX of the suction port inner wall surface distance. In FIG. 4, the magnitudes of the manufacturing tolerances ± t ₁ and ± t _{2 and} the magnitudes of the differences between the medians r ₁ and r ₂ are extremely exaggerated for convenience of understanding.

  The rotor 11 in which the recess 15 is formed is formed by sintering (metal powder sintering), and the sand plate 2A and the pump cover 2B, which are end section members in which the suction port 42 is formed, are formed by sand casting. Yes. Thus, the reason why different processing methods are used for the rotor 11 and the end section members 2A and 2B is to achieve both cost and product performance.

  In other words, when comparing metal powder sintering, which molds and sinters metal powder using a mold, and sand mold casting, metal powder sintering uses a mold and therefore has higher processing accuracy than sand mold casting. , Processing costs are also required. If only processing accuracy is regarded as important, metal powder sintering may be used not only for the rotor 11 but also for the sand plate 2A and the pump cover 2B, but this leads to an increase in cost. Therefore, the rotor 11 that requires processing accuracy is processed by sintering, and the sand plate 2A and the pump cover 2B that do not require relatively high processing accuracy are processed by sand casting.

  In the case of the rotor 11, not only the processing accuracy is required for the outer peripheral surface 14 and both end surfaces 17a and 17b, but also the processing accuracy is required for each part such as a large number of slit grooves 12, so that processing costs are incurred. Even processing by sintering is suitable. On the other hand, the sand plate 2A and the pump cover 2B require processing accuracy only for the main parts such as the surface that is in sliding contact with the rotor 11 and the surface that is joined to the pump housing 2, so that only the main part needs to be finished. Can be processed at low cost by casting.

The relationship between the manufacturing tolerance ± t ₁ of the rotor 11 where the recess 15 is formed and the manufacturing tolerance ± t ₂ of the sand plate 2A and the pump cover 2B where the suction port 42 is formed is also sintered in this way. Has high processing accuracy, but sand casting corresponds to the characteristic that processing accuracy is lower than this.

[Operation and effect of vane pump]
Since the vane pump according to the embodiment of the present invention is configured as described above, the following operations and effects can be obtained. That is, according to this vane pump, when the pump chamber 41 communicates with the suction port 42 by the rotation of the rotor 11, oil is sucked into the pump chamber 41 from the suction port 42, and then the pump chamber 41 communicates with the discharge port 43. Oil in the pump chamber 41 is discharged from the discharge port 43.

  On the outer peripheral surface 14 of the rotor 11 that forms the inner peripheral surface of the pump chamber 41, a protruding edge 16 that protrudes outward along both edges of the slit groove 12 is extended. Since the recess 15 is formed in the groove 15, the depth of the slit groove 12 is secured, the stroke of the vane 11 can be secured, the strength and rigidity around the slit groove 12 can be secured, and the formation of the recess 15 Since a sufficient oil suction area can be secured, it is possible to suppress the occurrence of cavitation that tends to occur during oil suction during high-speed operation of the pump.

  However, if the actual magnitude relationship between the distance from the pump shaft center 1c of the bottom surface of the concave portion 15 and the distance from the pump shaft center 1c of the suction port inner wall surface 42a is different for each pump, there is an uneven relationship with the oil flow path. Since the suction port side and the pump chamber 41 side are different from each other, there is a possibility that the variation in performance of each pump becomes large. Therefore, in the present vane pump, the wall surface 42 a on the pump shaft center side of the suction port 42 is configured to be closer to the pump shaft center 1 c than the bottom surface 15 a of the recess 15. Thus, when the suction port inner wall surface 42a is set at a position closer to the pump shaft center 1c than the bottom surface 15a of the recess 15, the suction port inner wall surface 42a is more than the bottom surface 15a of the recess 15 even if manufacturing errors are included. Suppressing protrusion prevents the actual magnitude relationship between the distance from the pump shaft center 1c of the bottom surface 15a of the recess 15 and the distance from the pump shaft center 1c of the suction port inner wall surface 42a from being different for each pump. can do.

In the present embodiment, the maximum value r _1MAX and intake port inner wall surface including the manufacturing tolerance ± t ₂ of the distance from the pump axis 1c of the bottom surface 15a of the recess 15 including the manufacturing tolerance ± t ₁ (bottom surface of the recess distance) The maximum value r _2MAX of the distance from the pump shaft center 1c of 42a (intake port inner wall surface distance) is set equal.

  Thereby, in particular, the suction port inner wall surface 42a does not protrude from the bottom surface 15a of the recess 15 even in the most severe state where each distance becomes the maximum value and the suction area is minimized. Therefore, adverse effects on the suction port 42 side (that is, loss during oil flow caused by a difference between the flow area on the suction port side and the suction area of the pump chamber) can be eliminated, and the performance required for the vane pump can be reduced. Can be secured.

  Further, if the suction area is increased by bringing the bottom surface 15a of the recess 15 close to the pump shaft 1c, an effect of suppressing the occurrence of cavitation can be obtained, but in order to increase the suction area, the bottom surface 15a of the recess 5 is The closer to the pump shaft 1c, the deeper the recess 15 becomes, and the more oil remains in the recess 15 after the oil is discharged from the pump chamber 41. As a result, the amount of air remaining in the recess 15 also increases, and on the contrary, the suction property deteriorates. That is, if the recess 15 is too deep or too shallow, the suction performance is deteriorated, so it is difficult to improve the total performance of the vane pump.

Therefore, in the present embodiment, the manufacturing tolerance t ₁ of the rotor 11 having the recess 15 is set to be smaller than the manufacturing tolerance t ₂ of the end section members 2A and 2B. As described above, the recess of the rotor ensures the suckability by reducing the manufacturing tolerance t ₁ so that the depth of the recess 15 does not become too deep or too shallow for each product. On the other hand, the end sections member 2A, manufacturing tolerances t ₂ of 2B, since the higher the rotor 11 processing accuracy is not required, the manufacturing tolerance t ₂ is made larger, thereby suppressing an increase in manufacturing cost.

  Further, in the present embodiment, not only is the outer peripheral surface 14 having both the recesses 15 and the both end surfaces 17a and 17b having a recess 15 that deteriorates the suckability even if too deep or too shallow, not only processing accuracy is required, but also a large number of slit grooves 12 are formed. The rotor 11 that requires machining accuracy in each part, etc., is an end partition member that requires relatively high machining costs but is processed by metal powder sintering with high machining accuracy, and only the main part is partially finished. The (sand plate 2A and pump cover 2B) are processed by sand casting at a relatively low processing cost. For this reason, it is possible to suppress the increase in cost while ensuring the necessary accuracy of the vane pump and improving the performance.

In the present embodiment, the positional relationship between the inner wall surface 42a of the suction port 42 and the bottom surface 15a of the recess 15 is set in consideration of manufacturing tolerances important in manufacturing management. That is, the manufacturing tolerance t ₁ of the rotor 11 having the recess 15 is set smaller than the manufacturing tolerance t ₂ of the end section members 2A and 2B, and the pump shaft of the bottom surface 15a of the recess 15 including the manufacturing tolerance ± t ₁ is set. The maximum value r _1MAX of the distance from the core 1c (the recess bottom surface distance) and the maximum value r _2MAX of the distance from the pump shaft center 1c of the suction port inner wall surface 42a including the manufacturing tolerance ± t ₂ (suction port inner wall surface distance) Are set equal to each other.

Further, the rotor 11 processed using metal powder sintering can reduce the manufacturing tolerance t ₁ , whereas the end section members (sand plate 2A and pump cover 2B) processed using sand casting are used. it is difficult to reduce the manufacturing tolerances t _2. The configuration according to the present embodiment in which the manufacturing tolerance t ₁ of the rotor 11 is set smaller than the manufacturing tolerance t ₂ of the end section members 2A and 2B is also used for this characteristic.

  Thus, according to the present vane pump, while suppressing an increase in manufacturing cost, the occurrence of discharge flow rate pulsation and discharge pressure pulsation due to air in the oil remaining in the recess 15 is suppressed, and the bottom surface position of the recess with a small manufacturing tolerance. Therefore, it is possible to suppress the occurrence of cavitation by securing an oil sucking area into the pump chamber substantially corresponding to the above, and to improve the total performance of the vane pump.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and implemented without departing from the spirit of the present invention. For example, if the manufacturing tolerance of the bottom surface of the recess and the manufacturing tolerance of the suction port inner wall surface, which is the wall surface on the pump shaft center side of the suction port, are set to the same level, the suction port wall surface of the suction port on the pump shaft center side It is preferable to set the inner wall surface of the port at a position closer to the pump shaft center than the bottom surface of the recess by a certain amount or more.

  Alternatively, regardless of the size of the manufacturing tolerance of the bottom surface of the recess and the manufacturing tolerance of the suction port inner wall surface, which is the wall surface on the pump shaft center side of the suction port, the pump axis 1c of the bottom surface 15a of the recess 15 including the manufacturing tolerance. It is also effective to set the minimum value of the distance from the intake port inner wall surface 42a including the manufacturing tolerance larger than the maximum value of the distance from the pump shaft center 1c. In this case, the suction port inner wall surface 42a can be reliably set at a position closer to the pump shaft center 1c than the bottom surface 15a of the recess, and the variation in performance of each vane pump can be suppressed more reliably.

  The present invention can be widely applied as an oil pump, and is particularly effective in promoting downsizing and speeding up of the pump.

Claims (6)

A rotor in which a plurality of slit grooves are radially formed on the outer peripheral surface in the pump housing, a vane accommodated in the slit grooves so as to be able to protrude and retract, and a tip of each vane disposed on the outer periphery of the rotor. A cam ring having a cam surface in contact with an inner periphery thereof, and end partition members respectively provided at both axial ends of the rotor, the outer peripheral surface of the rotor, the cam surface, the wall surface of the adjacent vane, and Each of the pump chambers is formed by being surrounded by the end partition member, and the end partition member includes a suction port for sucking oil into the pump chamber and a discharge port for discharging oil from the pump chamber. There,
The outer peripheral surface of the rotor between the slit grooves constituting the inner periphery of each pump chamber is recessed at the center portion between the both ends rather than the circumference connecting the tips of the ends where the slit grooves are formed. A recess is formed,
A vane pump in which a suction port inner wall surface, which is a wall surface on the pump shaft center side of the suction port, is set at a position closer to the pump shaft center than a bottom surface of the recess.   The maximum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance and the maximum value of the distance from the pump shaft center of the inner surface of the suction port including the manufacturing tolerance are set to be equal. The vane pump according to claim 1.   The vane pump according to claim 1 or 2, wherein one of the manufacturing tolerances of the bottom surface of the recess and the manufacturing tolerance of the inner wall surface of the suction port is set to be relatively small.   The vane pump according to claim 1 or 2, wherein a manufacturing tolerance of the bottom surface of the recess is set smaller than a manufacturing tolerance of the inner wall surface of the suction port.   The minimum value of the distance from the pump shaft center of the bottom surface of the recess including the manufacturing tolerance is set to be larger than the maximum value of the distance from the pump shaft center of the inner wall surface of the suction port including the manufacturing tolerance. Item 1. A vane pump according to item 1.   The vane pump according to claim 4 or 5, wherein the rotor is formed by sintering, and the end section member is formed by sand casting.

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