JP2012137047A - Vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vane pump that maintains intake performance to a working fluid containing air.SOLUTION: The vane pump 1 used as a fluid pressure supply source includes: a rotor 2 that is rotated and driven; a plurality of slits 5 that open radially on the rotor 2; a plurality of vanes 3 that project from the slits 5 so as to be slidable; an inner peripheral cam surface 4a that makes a tip of the vane 3 slidingly contact therewith; a vane chamber 7 that is defined among the inner peripheral cam surface 4a, the vane 3, and the rotor 2; and a vane-chamber drain passage 12 that makes air contained in the working fluid flow out from the vane chamber 7 in a transition region where the vane 7 changes from a discharge region to a suction region.

Description

  The present invention relates to a vane pump used as a fluid pressure supply source.

  In a conventional vane pump, a plurality of vanes are stored in radial slits of the rotor. As the rotor rotates, the vane slidingly contacting the inner circumferential cam surface of the cam ring reciprocates to expand and contract the vane chamber, and hydraulic oil is sucked from the suction port into the vane chamber in the suction region where the vane chamber expands. The hydraulic oil is discharged from the vane chamber to the discharge port in the discharge region where the vane chamber contracts.

  This type of vane pump is disclosed in Patent Document 1, for example.

Japanese Patent Laid-Open No. 10-266978

  However, in such a conventional vane pump, when the operating oil is agitated by touching the rotating body, and the air content in the operating oil is increased in the operation state in which air (bubbles) is included in the operating oil, The pumping action of the vane pump may be impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vane pump that maintains the suction performance of a working fluid containing air.

  The present invention is a vane pump used as a fluid pressure supply source, which is a rotor that is rotationally driven, a plurality of slits that open radially to the rotor, a plurality of vanes that slidably protrude from the slit, An inner peripheral cam surface that slides the tip of the vane, a vane chamber defined between the inner peripheral cam surface, the vane, and the rotor, and a transition region in which the vane chamber transitions from the discharge region to the suction region. And a vane chamber drain passage communicating with the vane chamber.

  According to the present invention, when the working fluid supplied to the vane chamber contains air, the compressed air together with a part of the working fluid is transferred in the transition region where the vane chamber transitions from the discharge region to the suction region. It escapes from the vane chamber to the outside of the vane chamber through the vane chamber drain passage. Thereby, it is suppressed that the air compressed with the working fluid by the vane chamber is carried to the suction region, the suction of the working fluid is smoothly performed in the suction region, and the suction performance of the vane pump is maintained.

The front view which shows the state which removed the pump cover of the vane pump which shows embodiment of this invention. The front view of a side plate similarly. The front view of a pump cover similarly. Similarly the front view of a rotor. The front view which similarly shows the operating state of a vane pump. The front view of the rotor which shows other embodiment of this invention. The front view of the rotor which shows other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  The vane pump 1 shown in FIGS. 1 to 3 is used as a hydraulic supply source for a hydraulic device mounted on a vehicle, for example, a transmission, a power steering device, or the like.

  The vane pump 1 uses a working oil (oil) as a working fluid, but a working fluid such as a water-soluble alternative liquid may be used instead of the working oil.

  In the vane pump 1, the power of an engine (not shown) is transmitted to the end of the drive shaft 9, and the rotor 2 connected to the drive shaft 9 rotates. The rotor 2 rotates in the direction indicated by the arrow in each figure.

  The drive shaft 9 is rotatably supported by the pump body 10 and the pump cover 50. The pump body 10 is formed with a pump housing recess 10a in which the rotor 2, the cam ring 4, the side plate 30 and the like are housed. A pump cover 50 is fastened to the pump body 10, and the pump housing recess 10 a is sealed by the pump cover 50.

  A high pressure chamber (not shown) is defined between the bottom of the pump housing recess 10 a of the pump body 10 and the side plate 30. The side plate 30 is pressed against the rear end surface of the cam ring 4 by the pump discharge pressure guided to the high pressure chamber.

  A plurality of vanes 3 are interposed between the cam ring 4 and the rotor 2. The rotor 2 is formed with a plurality of slits 5 radially with a predetermined interval. The vane 3 has a rectangular plate shape and is slidably inserted into the slit 5.

  A back pressure chamber 6 is defined between the rear end of the slit 5 and the base end of the vane 3, and pump discharge pressure is guided to the back pressure chamber 6. The vane 3 is urged in a direction protruding from the slit 5 by the pressure of the back pressure chamber 6 that presses the base end portion thereof and the centrifugal force that works as the rotor 2 rotates, and the tip end portion of the cam ring 4 is It is in sliding contact with the inner circumferential cam surface 4a.

  The cam ring 4 is an annular member whose inner circumferential cam surface 4a has a substantially oval shape. As the rotor 2 makes one revolution, each vane 3 following the inner peripheral cam surface 4a reciprocates twice.

  Inside the cam ring 4, a plurality of vane chambers 7 are defined by the inner peripheral cam surface 4 a of the cam ring 4, the outer periphery of the rotor 2, and the adjacent vanes 3.

  As shown in FIG. 2, the vane pump 1 includes a first suction region and a first discharge region where the vane 3 reciprocates for the first time, and a second suction region where the vane 3 reciprocates for the second time. And a second discharge region region. In the first and second suction regions, the volume of the vane chamber 7 expands as the rotor 2 rotates. In the first and second discharge regions, the volume of the vane chamber 7 contracts as the rotor 2 rotates.

  As described above, the vane pump 1 has two suction regions and two discharge regions, but is not limited thereto, and may have a configuration having one suction region and one discharge region, and may have three or more suction regions. And it is good also as a structure which has three or more discharge area | regions.

  The rotor 2 has two rotor end faces 2c orthogonal to the rotation center axis. The front rotor end surface shown in FIGS. 1 and 4 is in sliding contact with the end surface 55 of the pump cover 50. The rear rotor end surface 2 c is in sliding contact with the end surface 35 of the side plate 30.

  As shown in FIG. 2, the end surface 35 of the side plate 30 has a first suction port 31 opened in the first suction region, a first discharge port 32 opened in the first discharge region, and a second The second suction port 33 opens in the suction region, and the second discharge port 34 opens in the second discharge region.

  As shown in FIG. 3, a first suction port 51 is opened in the first suction region and the first discharge port 52 is formed in the first discharge region on the end surface 55 of the pump cover 50 where the rotor 2 is in sliding contact. Open, the second suction port 53 opens in the second suction area, and the second discharge port 54 opens in the second discharge area.

  The first suction port 31, the second suction port 33, the first suction port 51, and the second suction port 53 communicate with a tank (not shown) through the suction passage 25, and hydraulic oil from the tank is guided. .

  The first discharge port 32 and the second discharge port 34 communicate with hydraulic equipment via a pump discharge passage (not shown), and pressurized hydraulic fluid discharged from the first discharge port 32 and the second discharge port 34. Is supplied to the hydraulic equipment.

  As shown in FIG. 4, the rotor outer peripheral portion 20 that defines the vane chamber 7 of the rotor 2 includes a rotor outer peripheral convex portion 24 in which each slit 5 opens, and a rotor recessed in a concave shape with respect to the rotor outer peripheral convex portion 24. It has an outer periphery bore portion 21.

  The rotor outer periphery convex part 24 is a part which protrudes in a mountain shape from the outer periphery of the rotor 2, and one end of the slit 5 is opened at the center part thereof.

  The rotor outer peripheral convex portion 24 is formed in a cylindrical surface centered on the rotation center axis of the rotor 2 and has a predetermined minimum gap on the inner peripheral cam surface 4a of the cam ring 4 in a transition region between a suction region and a discharge region, which will be described later. Hold and confront (see FIG. 5).

  The rotor outer peripheral bore portion 21 is a portion that is recessed in a concave shape between adjacent rotor outer peripheral convex portions 24, an inclined portion 22 that extends inclined from each rotor outer peripheral convex portion 24, and the rotation of the rotor 2 from the inclined portion 22. And a bottom portion 23 extending in a cylindrical surface centered on the central axis.

  In the vane chamber 7, the area defined by the rotor outer peripheral bore 21 faces the suction ports 31, 33, 51, 53, so that the opening area for the suction ports 31, 33, 51, 53 is increased. Thus, even when the rotor 2 rotates at high speed, the hydraulic oil is smoothly sucked into the vane chamber 7 from the suction ports 31, 33, 51, 53, and the occurrence of cavitation or the like can be suppressed.

  By the way, for example, when the hydraulic oil in the transmission oil is agitated by touching the rotating body and the air content in the hydraulic oil increases in an operating state in which the hydraulic oil contains air (bubbles), the pumping action of the vane pump 1 is increased. Could be damaged.

  In particular, in the vane pump 1 in which the rotor 2 has the rotor outer periphery 21, the hydraulic fluid containing the air compressed in the discharge region passes through the rotor outer periphery in the transition region where the discharge region transitions from the discharge region to the suction region. After being once trapped in the vane chamber 7 defined by the section 21, the air contained in the hydraulic oil is expanded in the suction area and expanded, so that air is contained in the suction ports 31, 33, 51, 53. The rate may increase and the pumping action of the vane pump 1 may be impaired.

  In response to this, the present invention includes a vane chamber drain passage 12 that communicates the inside of the vane chamber 7 with the outside of the vane chamber 7 in the transition region in which the vane chamber 7 transitions from the discharge region to the suction region. The hydraulic fluid containing compressed air confined in the vane chamber 7 in the transition region is configured to escape to the outside through the vane chamber drain passage 12.

  The vane chamber drain passage 12 is opened to the rotor outer peripheral portion 20 (rotor outer peripheral bore portion 21) and the front rotor end surface 2c and communicates with each vane chamber 7 and the end surface of the pump cover 50. 55 and the casing side drain passage 15 opened to the end face 55 with which the rotor 2 is in sliding contact.

  FIG. 4 is a front view of the rotor 2 as viewed from the front side. On the rotor end surface 2 c on the front side of the rotor 2, the same number of rotor side drain passages 13 as the vane chambers 7 are formed.

  The rotor side drain passage 13 is defined by an air escape groove 14 that opens in the rotor end surface 2c. The air escape grooves 14 are formed in a radial shape extending in the radial direction of the rotor 2 at equal intervals in the circumferential direction of the rotor 2.

  One end of the air escape groove 14 opens to the rotor outer peripheral portion 20 (the bottom portion 23 of the rotor outer peripheral bore portion 21), and the rotor-side drain passage 13 communicates with the vane chamber 7.

  As shown in FIG. 3, the casing-side drain passage 15 is defined by two air relief holes 16 that open to the end surface 55 of the pump cover 50. The air escape hole 16 communicates with the outside of the vane pump 1.

  One air relief hole 16 opens at the boundary between the second discharge region and the first suction region, and communicates with the discharge ports 34 and 54 in the transition region where the vane chamber 7 transitions from the discharge region to the suction region. When the air does not pass through and does not communicate with the suction ports 31, 51, the air escape grooves 14 communicate with each other.

  One air escape hole 16 opens at the boundary between the first discharge region and the second suction region, and communicates with the discharge ports 32 and 52 in the transition region where the vane chamber 7 transitions from the discharge region to the suction region. When the air does not pass through and does not communicate with the suction ports 33 and 53, the air escape grooves 14 communicate with each other.

  FIG. 5A shows an operating state in which one vane chamber 7 is in the second discharge region. At this time, the vane chamber 7 communicates with the discharge port 34, and the rotor-side drain passage 13 (air escape groove 14) does not communicate with the casing-side drain passage 15 (air escape hole 16). The defined vane chamber 7 is filled with hydraulic oil containing air compressed in the second discharge region.

  FIG. 5B shows an operating state in which the vane chamber 7 is located at the boundary between the second discharge region and the first suction region as the rotor 2 rotates as indicated by an arrow. . At this time, the vane chamber 7 is disconnected from the discharge port 34 by the vane 3, and the rotor side drain passage 13 (air escape groove 14) communicates with the casing side drain passage 15 (air escape hole 16). The vane chamber drain passage 12 is opened. When the vane chamber drain passage 12 is opened in this way, the hydraulic oil containing the air compressed in the vane chamber 7 passes through the rotor side drain passage 13 (air escape groove 14) and the casing side drain passage 15 (air escape hole 16). As a result, the vane pump 1 flows out of the vane pump 1, and the pressure in the vane chamber 7 decreases to near atmospheric pressure.

  In the operating state shown in FIG. 5 (b), the hydraulic oil gathers on the outer peripheral side of the vane chamber 7 due to the centrifugal force acting on the hydraulic oil, and the air (bubbles) contained in the hydraulic oil becomes the inner periphery of the vane chamber 7. Gather on the side. Since one end of the air escape groove 14 opens in the bottom 23 of the rotor outer peripheral bore 21, the air collected on the inner peripheral side of the vane chamber 7 is encouraged to flow into the air escape groove 14 and is included in the hydraulic oil. The discharged air can be efficiently discharged through the vane chamber drain passage 12.

  When the vane chamber 7 moves to the boundary of the first suction area as the rotor 2 further rotates, the vane chamber 7 has the rotor side drain passage 13 (air escape groove 14) and the casing side drain passage. 15 (air escape hole 16) is blocked, the vane chamber drain passage 12 is closed, and the suction ports 31 and 51 are communicated. At this time, the hydraulic oil having a low air content remains in the vane chamber 7, and the air compressed together with the hydraulic oil by the vane chamber 7 is suppressed from being conveyed to the first suction region. Since the pressure in the vane chamber 7 is reduced to near atmospheric pressure, the expansion of air in the hydraulic oil is suppressed in the first suction region, the hydraulic oil is smoothly sucked, and the suction performance of the vane pump 1 is improved. Maintained.

  At this time, also in the vane chamber 7 moving from the first discharge region to the second suction region, the vane chamber drain passage 12 is similarly opened, and the hydraulic oil containing the air compressed in the vane chamber 7 is supplied to the vane pump. 1 flows out to the outside, and the working oil is smoothly sucked in the second suction region.

  The vane pump 1 is accommodated in, for example, a transmission case, and hydraulic fluid flowing out from the vane chamber drain passage 12 is returned to the transmission case and stored.

  Hereinafter, the gist, operation, and effect of the present embodiment will be described.

  In the present embodiment, the vane pump 1 is used as a fluid pressure supply source, and is a rotor 2 that is rotationally driven, a plurality of slits 5 that radially open in the rotor 2, and a slidable projection from the slit 5. A plurality of vanes 3, an inner peripheral cam surface 4 a that slides the tips of the vanes 3, a vane chamber 7 defined between the inner peripheral cam surface 4 a, the vane 3, and the rotor 2, and the vane chamber In the transition region where 7 changes from the discharge region to the suction region, the vane chamber drain passage 12 communicates with the vane chamber 7.

  Based on the above configuration, when air is contained in the working fluid supplied to the vane chamber 7, the vane chamber 7 is compressed together with a part of the working fluid in the transition region where the discharge region transitions to the suction region. Air is released from the vane chamber 7 to the outside of the vane chamber 7 through the vane chamber drain passage 12. Thereby, it is suppressed that the working fluid containing the air compressed in the vane chamber 7 is carried to the suction region, the working fluid is smoothly sucked in the suction region, and the suction performance of the vane pump 1 is maintained. The

  In the present embodiment, the vane chamber drain passage 12 has a plurality of rotor side drain passages 13 that open to the rotor outer peripheral portion 20 and the rotor end surface 2c that define the vane chamber 7, and a portion (pump cover) where the rotor end surface 2c is in sliding contact. The casing side drain passage 15 is opened to the end face 55 of the 50.

  Based on the above configuration, in the transition region where the vane chamber 7 transitions from the discharge region to the suction region as the rotor 2 rotates, the discharge ports 32, 34, 52, 54 and the suction ports 31, 33, 51 are moved by the vane 3. , 53 at a timing when communication with the rotor side drain passage 13 is cut off, the casing side drain passage 13 communicates with the casing side drain passage 15 and the vane chamber drain passage 12 is opened.

  Accordingly, the discharge ports 32, 34, 52, 54 do not communicate with the vane chamber drain passage 12 via the vane chamber 7, and the working fluid flows out from the vane chamber 7 in the discharge region through the vane chamber drain passage 12. The vane chamber drain passage 12 does not impair the discharge performance of the vane pump 1.

  Further, the suction ports 31, 33, 51, 53 do not communicate with the vane chamber drain passage 12 via the vane chamber 7, and the air outside the pump is prevented from flowing back through the vane chamber drain passage 12, and the vane chamber drain The suction performance of the vane pump 1 is not impaired by the passage 12.

  The casing-side drain passage 15 is not limited to the air escape hole 16 that opens to the end face 55 of the pump cover 50, and the air escape hole 17 that opens to the end face 35 of the side plate 30 as shown by a two-dot chain line in FIG. 2. You may comprise by. The casing-side drain passage 15 is formed by two air escape holes 17 that are opened in the end face 35 of the side plate 30 and through holes (not shown) of the pump body 10 that allow the air escape holes 17 to communicate with the outside of the vane pump 1. Composed. In this case, the rotor side drain passage 13 is configured to open to the rear rotor end surface 2 c that is in sliding contact with the side plate 30 of the rotor 2.

  In the present embodiment, the rotor-side drain passage 13 is configured by an air escape groove 14 that opens across the rotor outer peripheral portion 20 and the rotor end surface 2c.

  Based on the above configuration, the vane chamber drain passage 12 is opened when the air escape groove 14 communicates with the casing-side drain passage 15 as the rotor 2 rotates.

  Based on the above configuration, the rotor 2 has the rotor outer peripheral bore portion 21, so that an opening area for the suction ports 31, 33, 51, 53 of the vane chamber 7 is secured, and the suction of the vane pump 1 is performed even when the rotor 2 rotates at high speed. Performance is ensured.

  Since the rotor 2 has the rotor outer peripheral bore portion 21, the volume of the vane chamber 7 is increased, so that the amount of the working fluid remaining in the vane chamber 7 is increased, but the working fluid containing air is passed from the vane chamber 7 to the vane chamber drain passage. By letting it escape through 12, it is possible to prevent the working fluid containing compressed air from being carried to the suction region, so that the suction performance of the vane pump 1 is maintained.

  In the present embodiment, the rotor 2 includes a rotor end surface 2 c orthogonal to the rotation center axis, a rotor outer peripheral convex portion 24 where the slit 5 opens, and a rotor outer peripheral recess portion that is recessed in a concave shape with respect to the rotor outer peripheral convex portion 24. 21.

  In addition, this invention is applicable not only to the vane pump 1 provided with the rotor 2 with the rotor outer periphery rounding part 21, but also to the vane pump provided with the disk shaped rotor which does not have a rotor outer circumference rounding part.

  As another embodiment, as shown in FIG. 6, the rotor-side drain passage 13 may be defined by a hole-shaped air escape through hole 18 that opens to the rotor outer peripheral portion 20 and the rotor end surface 2 c.

  One open end 18a of the air escape through hole 18 opens at the bottom 23 of the rotor outer periphery bore portion 21, and the other open end 18b opens at the rotor end surface 2c.

  In the transition region where the vane chamber 7 transitions from the discharge region to the suction region, the open end 18 b of the air escape through hole 18 communicates with the air escape hole 16 of the pump cover 50.

  As another embodiment, two casing-side drain passages 15 may be provided before and after the rotor 2.

  Specifically, one casing-side drain passage 15 is configured by an air escape hole 17 that opens in the end surface 35 of the side plate 30. The other casing-side drain passage 15 is constituted by an air escape hole 16 that opens in the end surface 55 of the pump cover 50.

  In this case, as shown in FIG. 7, the rotor-side drain passage 13 may be defined by an air escape slit 19 that opens in a slit shape across the rotor outer peripheral portion 20 and the two rotor end surfaces 2c.

  The air escape slit 19 has an opening 19a that opens at the bottom 23 of the rotor outer periphery 21 and an opening 19b that opens at each of the two rotor end surfaces 2c.

  In the transition region where the vane chamber 7 transitions from the discharge region to the suction region, the opening 19 b of the air escape slit 19 communicates with the air escape hole 17 of the side plate 30 and the air escape hole 16 of the pump cover 50.

  Thus, by providing the two casing-side drain passages 15 before and after the rotor 2, the working fluid containing air is quickly released to the outside of the vane pump 1.

  Instead of the air escape slit 19, a plurality of pairs of air escape grooves 14 and air escape through holes 18 opened on the front and rear end faces 2 c of the rotor 2 may be formed.

  Since the angle range of the transition region is small, the air escape slit 19 and the air escape through hole 18 need to be formed by cutting to ensure machining accuracy. On the other hand, even if the groove width is small, the air escape groove 14 can be formed integrally with a mold used when the rotor 2 is molded because the groove depth is small. Can be suppressed.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The vane pump of the present invention is not limited to a hydraulic device mounted on a vehicle, and can be used as a fluid pressure supply source for driving a load of, for example, a construction machine, a work machine, another machine, or a facility.

DESCRIPTION OF SYMBOLS 1 Vane pump 2 Rotor 2c Rotor end surface 3 Vane 4 Cam ring 4a Inner peripheral cam surface 5 Slit 6 Back pressure chamber 7 Vane chamber 12 Vane chamber drain passage 13 Rotor side drain passage 14 Air escape groove 15 Casing side drain passage 16, 17 Air escape hole 18 Air Escape Passing Hole 19 Air Escape Slit 20 Rotor Outer Perimeter 21 Rotor Outer Perimeter 24 Rotor Perimeter Protrusion 30 Side Plate 50 Pump Cover

Claims (6)

A vane pump used as a fluid pressure supply source,
A rotor that is driven to rotate;
A plurality of slits radially opening in the rotor;
A plurality of vanes protruding slidably from the slit;
An inner peripheral cam surface for slidingly contacting a tip of the vane;
A vane chamber defined between the inner circumferential cam surface, the vane and the rotor;
A vane pump comprising: a vane chamber drain passage communicating with the vane chamber in a transition region where the vane chamber transitions from a discharge region to a suction region. The rotor is
A rotor outer periphery that defines the vane chamber;
A rotor end surface orthogonal to the rotation center axis,
The vane chamber drain passage is
A plurality of rotor-side drain passages that open to the rotor outer peripheral portion and the rotor end surface;
The vane pump according to claim 1, further comprising: a casing-side drain passage that opens to a portion where the rotor end surface is in sliding contact.   3. The vane pump according to claim 2, wherein the rotor-side drain passage is defined by an air escape groove that opens across the outer periphery of the rotor and the end surface of the rotor.   3. The vane pump according to claim 2, wherein the rotor-side drain passage is defined by a hole-like air escape hole that opens to the outer periphery of the rotor and the end surface of the rotor.   3. The vane pump according to claim 2, wherein the rotor-side drain passage is defined by an air escape slit that opens in a slit shape across the outer periphery of the rotor and two end faces of the rotor. The outer periphery of the rotor is
A rotor outer peripheral convex portion in which the slit is opened;
The vane pump according to any one of claims 1 to 5, further comprising a rotor outer peripheral recess portion that is recessed in a concave shape with respect to the rotor outer peripheral convex portion.

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