JP4182349B2 - Oil pump - Google Patents

Description

  The present invention relates to an oil pump in which a belt-shaped annular filter is wound around an outer surface and an oil suction portion is provided inside the filter.

The conventional oil pump shown in FIG. 6 includes an annular filter 4 between an inner wall 2 surrounding the rotor 1 and an outer wall 3 surrounding the inner wall 2, and passes through a pipe line 3 </ b> A extending from the outer wall 3. It was the structure which attracts | sucks oil (for example, refer patent document 1). In contrast to this oil pump, the conventional oil pump shown in FIG. 7 is provided with a belt-like ring-shaped filter 4 on the outer surface in order to widen the opening of the oil suction portion and reduce the suction resistance, and the oil inside the filter 4 It has a structure with a suction part. And the oil which passed the filter 4 is attracted | sucked to the rotor 1 side through the suction port 3B of the inner and outer surrounding walls 2 and 3 with which the oil suction part was equipped. The filter 4 is provided with a number of fine holes through which oil can circulate and prevent foreign matter from entering, and is integrated with a plurality of synthetic resin ribs 5 that support the holes. Further, when excessively high pressure oil is discharged to the discharge side of the rotor 1, the excess oil is returned to the oil suction portion from the discharge port 6 formed between the inner and outer surrounding walls 2 and 3. It was like that.
JP-A-6-74014 (paragraphs [0008] and [0009], FIG. 1)

  However, the oil pump shown in FIG. 7 has an outer edge region 5A closed by the filter 4, the outer surrounding wall 3 and the pair of ribs 5 and 5, and about half of the total area of the filter 4 is about 50%. It faced the closed outer edge region 5A. For this reason, the oil sucked from the suction port 3B is sucked from substantially the remaining half of the entire area of the filter 4, the effective use of the filter 4 is not achieved, and the suction resistance is still high. When the suction resistance is large, the oil pressure near the suction port 3B becomes lower than the outside of the filter 4. In this state, since a necessary amount of oil must be sucked into the rotor 1, the oil pressure when sucked into the rotor 1 further decreases. At this time, cavitation occurs. Cavitation is a phenomenon in which liquid becomes bubbles as a result of the pressure decreasing to the saturated vapor pressure of the liquid. When the pressure of the oil increases as the rotor 1 rotates, the bubbles are crushed instantaneously and disappear. At this time, there is a problem that noise is generated. Also, when oil is discharged to the discharge port 6, bubbles are generated due to cavitation because the oil flows at a high speed due to the pressure difference of the oil. If the air bubbles are sucked into the rotor 1 again without disappearing and the oil pressure is increased, the air bubbles are momentarily crushed and noise is generated. Furthermore, there is a problem that the oil suction efficiency of the oil pump is lowered due to the large suction resistance.

  The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide an oil pump capable of reducing the suction resistance as compared with the prior art. Is to provide a pump.

In order to achieve the above object, an oil pump according to the invention of claim 1 is an oil pump in which a belt-shaped ring-shaped filter is wound around an outer surface, and an oil suction portion is provided inside the filter. The part is provided with a rotor, an inner surrounding wall surrounding the rotor, and an outer surrounding wall surrounding the inner surrounding wall, and suction ports connected to the inside and outside of each surrounding wall are formed on the inner and outer surrounding walls, respectively. In an oil pump in which oil is sucked to the rotor side through the filter and the suction port by rotating the rotor, the outer edge portion of the oil suction part has a plurality of filters that hold the filter from the outer surrounding wall. A rib is formed, and a communication path for connecting an outer edge region surrounded by the filter and the outer surrounding wall and the plurality of ribs to the suction port is connected to the filter Formed between the side enclosure, the flow path of the oil passing through the rotor flow operates when the internal pressure of the flow path is increased beyond a predetermined value, returning the oil in the channel to the oil suction portion A relief valve is provided, and the oil return port from the relief valve is arranged outside the outer wall .

According to a second aspect of the present invention, in the oil pump according to the first aspect , a part of the outer surface of the outer surrounding wall is curved toward the side away from the filter to form a curved part, and the periphery is closed by the curved part and the filter. It has a feature in that a return port is arranged in the area.

[Invention of Claim 1]
In the oil pump according to claim 1, since the outer edge region surrounded by the plurality of ribs, the filter, and the outer surrounding wall is connected to the suction port by the communication path, not only the portion of the filter facing the suction port but also the outer edge. Oil can also be sucked from the portion facing the region. Thereby, the passage area of the oil in the filter becomes wider than before, and the suction resistance can be reduced.

In the oil pump of the present invention , since the oil return port from the relief valve is arranged outside the outer wall, the path from the oil return port to the rotor becomes long. For this reason, even if bubbles are generated by cavitation, the rate of disappearance is increased by the bubbles being dissolved in the oil before being sucked into the rotor. Unlike the case where bubbles collapse and disappear instantaneously in a high-pressure environment in the rotor, no noise is generated in this case. Thereby, it becomes possible to reduce noise more than before.

[Invention of claim 2 ]
In the oil pump according to the second aspect, the oil return port from the relief valve is disposed in a region where the periphery is closed by the curved portion formed in the outer surrounding wall and the filter. In this closed region, high-pressure oil is recirculated from the relief valve, and this oil flows out through the filter. In this region, the oil pressure is higher than that outside the filter. For this reason, generation | occurrence | production of the bubble by cavitation is suppressed. Also, since the oil pressure in this region is higher than the outside of the filter, the bubbles are likely to be dissolved in the oil. In addition, since it is difficult for the bubbles to pass through the filter, it is possible to further suppress the bubbles from flowing out of the filter. Thereby, it becomes possible to reduce noise more than before.

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 shows an outer surface shape of an oil pump 10 according to the present embodiment. In FIG. 1, reference numeral 11 denotes a housing, which is formed on one end surface of a housing main body 12 flattened in the vertical direction of the figure. A valve housing portion 13 is provided.

  As shown in FIG. 2, the housing body 12 is provided with a pair of opposed substrates 14 and 14 that face each other. An inner wall 20 and an outer wall 30 according to the present invention are formed to protrude on the opposite surface of one counter substrate 14, and both the counter substrates 14, 14 are bolted with the inner and outer walls 20, 30 in between. Yes. Thereby, a space open to all sides is formed between the opposing substrates 14 and 14. The open portion of the space is closed by a band-shaped annular filter 17A wound around the housing body 12. As shown in FIG. 3, the filter 17 </ b> A forms a filter unit 17 integrally with the reinforcing member 18, and is disposed between the counter substrates 14 and 14 in this state. With this structure, the cost is reduced and the assemblability when the oil pump is manufactured is improved. Among the constituent elements of the reinforcing member 18, a plurality of support portions provided in a direction crossing the filter 17A are ribs 18A, and an annular support portion 18B supports both ends of the ribs 18A along the filter 17A.

  An inner portion of the filter 17 </ b> A in the housing 11 is an oil suction portion 19 including the inner wall 20 and the outer wall 30. As shown in FIG. 4, the inner wall 20 has an annular shape, and an elliptical hole 44 is formed inside the inner wall 20. The rotor 40 is accommodated in the elliptical hole 44. The rotor 40 includes a plurality of wing portions 42 that project radially from the rotating body 41. The wing portion 42 can be linearly moved in the radial direction of the rotating body 41 and is urged in a direction protruding from the rotating body 41. Then, the rotating body 41 rotates while the tip of the wing portion 42 is in sliding contact with the inner peripheral surface of the elliptical hole 44.

  The inner wall 20 is connected to the inside and outside of the inner wall 20 in two regions that are arranged in a point-symmetric manner among the four regions divided into four equal parts by the major axis L1 and the minor axis L2 of the elliptical cross section of the elliptical hole 44. A pair of suction ports 21 and 21 are formed. In the remaining two of the four regions, the oil suction / feed passage 43 is formed to be recessed in the inner peripheral surface of the elliptical hole 44 and extends in the axial direction of the elliptical hole 44. Then, the oil taken in from the suction port 21 between the adjacent wing parts 42, 42 is compressed by flowing toward the short axis L <b> 2 side of the elliptical hole 44 and flows into the oil suction / feed path 43.

  The outer surrounding wall 30 is formed so as to surround the inner surrounding wall 20. Suction ports 31, 31 that connect the outer surrounding wall 30 to the inside and outside are formed in portions of the outer surrounding wall 30 that face the suction ports 21, 21 of the inner surrounding wall 20. More specifically, the outer surrounding wall 30 is provided with a pair of outer surrounding wall constituting portions 32 and 32 opposed in the vertical direction in FIG. 4, and the space between these outer surrounding wall constituting portions 32 and 32 is the inner surrounding wall 20. Is a pair of suction ports 31 and 31 that open to both sides. One suction port 31 is divided into two by a part of the outer surrounding wall 30 left between the outer surrounding wall constituting portions 32 and 32.

  The plurality of ribs 18 </ b> A of the filter unit 17 include a rib 50 provided to face the suction port 31, a rib 51 formed to protrude from an outer surface of the outer surrounding wall 30 at an intermediate portion away from the suction port 31, and an outer surrounding wall. 30 is divided into ribs 52 formed at positions spaced outward from the end near suction port 31. These ribs 50, 51, 52 support the filter 17 </ b> A so that it does not sink inside the oil suction portion 19. An outer edge region 53 surrounded by the filter 17A, the outer surrounding wall constituting portion 32, and the plurality of ribs 51 and 52 is formed by a communication path 53A formed between the filter 17A and the outer surrounding wall 30 spaced from the outer surrounding wall 30. The suction port 31 communicates. The cross-sectional area of the communication path 53A with respect to the oil flow direction is preferably at least 30 square millimeters so that the oil flows smoothly.

  By the way, the oil sucked into the oil suction / feed passage 43 by the rotation of the rotor 40 passes through the flow path 60 in the housing 11 shown in FIG. 2 and is fed to a predetermined location. A relief valve 61 is provided in the middle of the flow path 60. When the pressure in the flow path 60 becomes equal to or higher than a predetermined pressure, the relief valve 61 is actuated to remove oil in the flow path 60 from the oil. Return to the suction part 19. Here, in the present embodiment, as shown in FIG. 4, the oil return port 62 that has passed through the relief valve 61 is disposed in a region surrounded by the outer surrounding wall 30 and the filter 17 </ b> A. More specifically, a curved portion 63 is formed by curving between the pair of ribs 51, 51 in contact with the outer surrounding wall 30 of the outer surrounding wall 30 toward the side away from the filter 17 </ b> A. Then, the ribs 51 and 51 at both ends of the bending portion 63 are in contact with the filter 17A, so that the return port 62 is opened to a region closed by the bending portion 63 and the filter 17A.

Next, the operation and effect of this embodiment configured as described above will be described.
The oil pump 10 is used in a state where the portion around which the filter 17A is wound is immersed in the oil in the oil tank. When the oil pump 10 is started, the rotor 40 rotates and the oil suction part 19 inside the filter 17A is in a negative pressure state. Here, the outer edge region 53 surrounded by the filter 17A, the outer surrounding wall 30, and the plurality of ribs 51, 52 communicates with the suction port 31 through the communication path 53A between the rib 52 and the outer surrounding wall 30. The outer edge region 53 is also in a negative pressure state. Accordingly, the oil can be sucked not only from the portion facing the suction port 31 in the filter 17A but also from the portion facing the outer edge region 53. As a result, the oil passage area in the filter 17A becomes wider than before, and the suction resistance can be reduced, thereby making it possible to save energy.

  By the way, the oil that has passed through the rotor 40 in the oil pump 10 flows into the flow path 60, and is further supplied to a servo valve, an actuator, or the like connected from the end of the flow path 60. Here, when the oil supplied to the servo valve, the actuator or the like decreases, the pressure in the flow path 60 increases. And when the pressure in the flow path 60 becomes more than predetermined pressure, the relief valve 61 provided in the flow path 60 will act | operate, and the oil in the flow path 60 will be returned in an oil tank. Here, since the return port 62 of the relief valve 61 is disposed in a region closed around by the curved portion 63 formed in the outer surrounding wall 30 and the filter 17A, the return port 62 is discharged from the return port 62 of the relief valve 61. The oil is discharged out of the filter 17A and then sucked into the rotor 40 through the filter 17A again. As a result, the pressure at the return port 62 is increased by the filter 17A from the return port 62 to the rotor 40, and cavitation is suppressed, so that noise can be reduced as compared with the prior art.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following are within the scope not departing from the gist. It can be changed and implemented.

  (1) As shown in FIG. 5, the ribs 52 and 52 at both ends of the bending portion 63 are separated from the outer surrounding wall 30, and the inner region of the bending portion 63 communicates with the suction port 31 through the outer edge region 53. It may be. Also with this configuration, since the pressure at the return port 62 from the relief valve 61 is higher than in the conventional oil pump, cavitation can be suppressed.

  (2) In the above-described embodiment, the oil pump including the wing-type rotor has been described. However, the configuration of the rotor is not limited thereto, and the present invention is applied to, for example, an oil pump including a trochoid type rotor. You may apply.

The side view of the oil pump concerning one embodiment of the present invention. Oil pump side sectional view Perspective view of filter Sectional drawing of the oil pump in the AA cross section of FIG. Sectional drawing of the oil pump of the modification 1 Cross section of conventional oil pump Cross section of conventional oil pump

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Oil pump 17 Filter unit 17A Filter 18A, 50, 51, 52 Rib 19 Oil suction part 20 Inner wall 21 Inner suction port 30 Outer wall 31 Outer suction port 40 Rotor 53 Outer edge area 60 Flow path 61 Relief valve 62 Return port 63 Curve Part

Claims (2)

An oil pump in which a belt-shaped ring-shaped filter is wound around an outer surface and includes an oil suction portion inside the filter. The oil suction portion includes a rotor, an inner wall surrounding the rotor, and the inner wall. Surrounding outer walls are provided, and suction ports communicating with the inner and outer sides of the surrounding walls are formed in the inner and outer surrounding walls, respectively, and by rotating the rotor, oil is supplied to the filter and the suction. In the oil pump sucked to the rotor side through the port,
A plurality of ribs are formed on an outer edge portion of the oil suction part to hold the filter in a state of floating from the outer surrounding wall, and an outer edge region surrounded by the filter and the outer surrounding wall and the plurality of ribs is A communication path for communicating with the suction port is formed between the filter and the outer wall ;
The flow path into which the oil that has passed through the rotor flows is provided with a relief valve that operates when the internal pressure of the flow path rises above a predetermined value and returns the oil in the flow path to the oil suction section. And
An oil pump characterized in that an oil return port from the relief valve is disposed outside the outer wall . A part of the outer surface of the outer surrounding wall is curved to the side away from the filter to form a curved part, and the return port is arranged in a region closed by the curved part and the filter. The oil pump according to claim 1 .

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