JP2010190081A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump capable of self-adjustment of discharge pressuref while eliminating the need for a regulating valve or reducing the size of the regulating valve. <P>SOLUTION: On the front end surface of a blade 53, a seat face 531 and a pressure receiving face 532 are provided which contacts the inner peripheral face of a housing 51 and on which pressure in an operation chamber 55 (a front operation chamber) located on the rotor-rotating-direction front side of the blade 53 operates, respectively. With the pressure operating on the pressure receiving face 532, the blade 53 is energized so that the seat face 531 is moved apart from the inner peripheral face of the housing 51. When the pressure in the front operation chamber is higher, the seat face 531 is moved apart from the inner peripheral face of the housing 51 to communicate an operation chamber located on the rotor-rotating-direction back side of the blade 53 with the front operation chamber, thus reducing pump discharging efficiency to reduce discharging pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vane pump used for fluid transfer.

  A fuel supply device applied to a stock pressure fuel injection device for a diesel engine includes a high pressure pump that pumps high pressure fuel to a common rail, a feed pump that supplies fuel from a fuel tank to a high pressure pump, and a fuel that is supplied from the feed pump to the high pressure pump. And an intake metering valve that adjusts the amount of gas (for example, see Patent Document 1). As the feed pump, for example, a vane pump in which a plurality of blades are inserted into a blade groove of a rotor is used (see, for example, Patent Document 2).

JP 2000-240531 A JP 58-41287 A

  However, the fuel supply device disclosed in Patent Document 1 needs to be provided with a regulating valve in order to control the pressure of the fuel discharged from the feed pump to a predetermined value.

  Further, in the operation region where the target discharge amount of the high pressure pump is 0, it is necessary to return all of the fuel discharged from the feed pump to the feed pump suction side via the regulating valve. For this reason, it is necessary to secure a sufficient fuel passage area in the regulating valve, and there is a problem that the regulating valve is enlarged.

  The present invention has been made in view of the above points, and an object of the present invention is to obtain a vane pump capable of self-adjusting the discharge pressure to eliminate the need for a regulator valve or to reduce the size of the regulator valve.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of members surrounded by the inner peripheral surface of the housing (51), the side surface of the housing (51), the outer peripheral surface of the rotor (52), and the blade (53). In the vane pump in which the volume of the working chamber (55) changes as the rotor (52) rotates, a seat surface (531) in contact with the inner peripheral surface of the housing (51) is formed on the tip surface of the blade (53); And a pressure receiving surface (532) on which the pressure of the working chamber (55) located on the front side in the rotor rotation direction of the blade (53) acts.

  According to this, the blade (53) is urged by the pressure acting on the pressure receiving surface (532) so that the seat surface (531) is away from the inner peripheral surface of the housing (51). When the pressure in the working chamber located on the front side in the rotational direction (hereinafter referred to as the front working chamber) increases, the seat surface (531) moves away from the inner peripheral surface of the housing (51), and the blade (53) moves backward in the rotor rotational direction. The working chamber (hereinafter referred to as the rear working chamber) located on the side communicates with the front working chamber (55), the pump discharge efficiency is lowered, and the discharge pressure is lowered. In this way, since the vane pump can self-adjust the discharge pressure, the regulator valve is unnecessary or the regulator valve can be downsized.

  According to the second aspect of the present invention, in the vane pump according to the first aspect, the slit (522) guides the pressure of the working chamber (55) located on the rear side in the rotor rotation direction of the blade (53) into the blade groove (521). ) Is formed in the rotor (52).

  According to this, the pressure difference between the front working chamber (55) and the rear working chamber (55) can be adjusted to a substantially constant value or less.

  According to a third aspect of the present invention, in the vane pump according to the first aspect, a communication hole for guiding the pressure of the working chamber (55) located on the rear side in the rotor rotation direction of the blade (53) into the blade groove (521) ( 523) is formed in the rotor (52).

  According to this, the pressure difference between the front working chamber (55) and the rear working chamber (55) can be adjusted to a substantially constant value or less. Further, the communication hole (523) formed in the rotor (52) is easier to process than the slit formed in the rotor (52).

  According to a fourth aspect of the present invention, in the vane pump according to the first aspect, the slit (534) guides the pressure of the working chamber (55) located on the rear side in the rotor rotation direction of the blade (53) into the blade groove (521). ) Is formed on the blade (53).

  According to this, the pressure difference between the front working chamber (55) and the rear working chamber (55) can be adjusted to a substantially constant value or less. Further, the slit (534) formed in the blade (53) is easier to process than the slit formed in the rotor (52).

  As in the fifth aspect of the invention, in the vane pump according to any one of the first to fourth aspects, the pressure receiving surface (532) is inclined with respect to the tangent to the inner peripheral surface of the housing (51). Can be implemented.

  The invention according to claim 6 is characterized in that, in the vane pump according to any one of claims 1 to 4, a boundary portion between the seat surface (531) and the pressure receiving surface (532) is stepped. To do.

  According to this, the pressure in the front working chamber (55) acts more reliably on the entire pressure receiving surface (532) than when the pressure receiving surface (532) is inclined with respect to the tangent to the inner peripheral surface of the housing (51). Therefore, the operation of self-adjusting the discharge pressure is stabilized.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a typical lineblock diagram of an animal pressure type fuel injection device provided with a vane pump concerning one embodiment of the present invention. It is sectional drawing which shows the structure of the vane pump of FIG. 1 typically. It is an expanded sectional view of the A section of FIG. (A) is front sectional drawing which shows typically the structure of the principal part of a 1st modification, (b) is a right view of the braid | blade single-piece | unit of (a). (A) is front sectional drawing which shows typically the structure of the principal part of a 2nd modification, (b) is a right view of the braid | blade single-piece | unit of (a). It is sectional drawing which shows typically the structure of the principal part of a 3rd modification. It is sectional drawing which shows typically the structure of the principal part of a 4th modification.

  The vane pump of this embodiment is used for a fuel supply device of an accumulator fuel injection device in a vehicle internal combustion engine (more specifically, a diesel engine).

  As shown in FIG. 1, this accumulator type fuel injection device supplies a high pressure fuel to a common rail 1 that stores high pressure fuel, an injector 2 that injects high pressure fuel supplied from the common rail 1 into each combustion chamber of the internal combustion engine, and a common rail 1. And a fuel tank 41 for storing fuel, and a fuel filter 41 for filtering fuel.

  The common rail 1 is a livestock pressure means for storing high-pressure fuel supplied from the supply pump 3 while maintaining the target rail pressure. Note that the target rail pressure is determined by a control device (hereinafter referred to as an ECU) (not shown) based on the operation state of the diesel engine such as an accelerator opening signal and an engine speed signal, for example.

  The injector 2 is fuel injection means for injecting high-pressure fuel into the combustion chamber of the internal combustion engine. The injector 2 is supplied with high-pressure fuel from the common rail 1 via a high-pressure pipe 2a. The injector 2 is connected to the ECU, and the fuel injection timing and the injection amount are controlled by a control signal of the ECU.

  The supply pump 3 is a feed pump 5 that pumps fuel from a fuel tank 4, a high-pressure pump 6 that pressurizes and supplies fuel supplied from the feed pump 5 to the common rail 1, and a fuel flow rate that is supplied from the feed pump 5 to the high-pressure pump 6. And a regulating valve 8 for controlling the pressure of the fuel discharged from the feed pump 5 (hereinafter referred to as feed pressure) to a predetermined pressure.

  The feed pump 5 pumps fuel from the fuel tank 4 through the suction path 9a, and supplies the pumped fuel to the high-pressure pump 6 through the low-pressure discharge path 9b. In the present embodiment, a vane pump (described later in detail) is adopted as the feed pump 5, which is connected to the drive shaft 61 of the high-pressure pump 6, and a rotational driving force is transmitted from the drive shaft 61.

  The suction side and the discharge side of the feed pump 5 are connected by a relief path 9c, and a regulating valve 8 is disposed in the relief path 9c. When the feed pressure exceeds a predetermined pressure, the regulating valve 8 opens the relief path 9c and controls the feed pressure to a predetermined pressure.

  In the low-pressure discharge path 9b, the suction metering valve 7 is arranged downstream of the branch point of the relief path 9c. The intake metering valve 7 is a linear solenoid type electromagnetic valve configured such that the valve opening degree can be continuously changed, and the valve opening degree is determined by a control signal output from the ECU based on the operating state of the internal combustion engine. Is controlled.

  The high-pressure pump 6 includes a drive shaft 61 that is driven and rotated by an internal combustion engine, a plunger 62 that is reciprocated in the cylinder by driving force transmitted from the drive shaft 61, and the like. Connected to the drive shaft 61 is a cam 63 that converts the rotational motion of the drive shaft 61 into linear motion and transmits it to the plunger 62, and the cam 63 is disposed in a cam chamber 64 formed in the pump housing.

  A pressurizing chamber 65 whose volume changes in accordance with the reciprocating motion of the plunger 62 is formed in the cylinder of the high-pressure pump 6. A low-pressure discharge path 9b is connected to the pressurizing chamber 65, and only the flow of fuel from the feed pump 5 to the pressurizing chamber 65 is provided downstream of the intake metering valve 7 in the low-pressure discharge path 9b. A permissible intake valve 66 is arranged.

  The pressurizing chamber 65 is connected to the common rail 1 through the high-pressure discharge path 9d. A discharge valve 67 that allows only the flow of fuel from the pressurizing chamber 65 toward the common rail 1 is disposed in the high-pressure discharge path 9d.

  The high pressure pump 6 pressurizes the fuel supplied from the feed pump 5 by the reciprocating motion of the plunger 62 and feeds it to the common rail 1.

  The cam chamber 64 of the high-pressure pump 6 is connected to the discharge side of the feed pump 5 by the lubricating fuel path 9e, and a part of the fuel discharged from the feed pump 5 is guided to the cam chamber 64. The fuel guided to the cam chamber 64 acts as a lubricating oil for the sliding portion between the cam 63 and the plunger 62.

  As shown in FIGS. 2 and 3, the feed pump 5 includes a housing 51 having a cylindrical storage space formed therein, and a cylindrical rotor 52 is rotatably disposed in the storage space. Further, the drive shaft 61 inserted into the center of the rotor 52 is disposed at a position shifted from the center of the accommodation space. The dimension in the drive shaft direction in the accommodation space and the thickness of the rotor 52 are set to be substantially equal, and the side surface of the rotor 52 is in contact with the side surface of the housing 51. The rotor 52 has a plurality (four in this example) of blade grooves 521 drilled from the outer peripheral surface toward the center, and the blade grooves 521 are arranged at equal intervals along the circumferential direction.

  A blade 53 is inserted into the blade groove 521 so as to be movable in the rotor radial direction. The blade 53 is urged toward the outer side in the rotor radial direction by a spring 54 disposed in the blade groove 521, and a tip end surface thereof is in contact with the inner peripheral surface of the housing 51. Further, the side surface of the blade 53 in the drive shaft direction is in contact with the side surface of the housing 51.

  As a result, a plurality (four in this example) of working chambers 55 surrounded by the inner peripheral surface of the housing 51, the side surface of the housing 51, the outer peripheral surface of the rotor 52, and the blades 53 are formed. Thus, the volume of the working chamber 55 is changed.

  A suction port 511 and a discharge port 512 are provided on the side wall of the housing 51. The suction port 511 communicates with the working chamber 55 in the process of increasing the volume of the working chamber 55, and introduces fuel into the working chamber 55 from the suction port 511. The discharge port 512 communicates with the working chamber 55 in which the volume of the working chamber 55 is decreasing, and fuel is discharged from the working chamber 55 to the discharge port 512.

  2 and 3 indicate the rotation direction of the rotor 52, and is hereinafter referred to as the rotor rotation direction B. Of the two working chambers 55 located on both sides of each blade 53, the working chamber located on the front side in the rotor rotation direction B with respect to the blade 53 is hereinafter referred to as a front working chamber, and the rotor rotates with respect to the blade 53. The working chamber located on the rear side in the direction B is hereinafter referred to as a rear working chamber.

  A seat surface 531 in contact with the inner peripheral surface of the housing 51 is formed on the rear working chamber side of the front end surface of the blade 53, and is always separated from the inner peripheral surface of the housing 51 on the front working chamber side of the front end surface of the blade 53. Thus, a pressure receiving surface 532 on which the pressure of the front working chamber acts is formed. The pressure receiving surface 532 is inclined with respect to a tangent to the inner peripheral surface of the housing 51 at a portion where the seat surface 531 is in contact.

  The rotor 52 is formed with a slit 522 that guides the pressure in the rear working chamber into the blade groove 521. As a result, the pressure in the rear working chamber acts on the rear end surface 533 of the blade 53.

  Next, the operation of this embodiment in the above configuration will be described. During operation of the internal combustion engine, a rotational driving force is transmitted from the drive shaft 61 to the feed pump 5, and the feed pump 5 pumps fuel from the fuel tank 4 via the suction path 9a. The fuel discharged from the feed pump 5 is controlled to a predetermined feed pressure by the regulating valve 8 and flows into the high-pressure pump 6 through the low-pressure discharge path 9 b and the suction metering valve 7. The valve opening degree of the intake metering valve 7 is controlled by a control signal output from the ECU, and a fuel having a flow rate sufficient for the operation of the internal combustion engine flows into the high-pressure pump 6.

  In the high-pressure pump 6, the plunger 62 reciprocates following the cam 63. When the plunger 62 moves inside the cylinder toward the drive shaft 61, the volume of the pressurizing chamber 65 increases and the pressure in the pressurizing chamber 65 decreases. As a result, the intake valve 66 is opened and the fuel that has passed through the intake metering valve 7 is sucked into the pressurizing chamber 65.

  Further, when the plunger 62 moves inside the cylinder toward the counter drive shaft, the volume of the pressurizing chamber 65 decreases and the fuel sucked into the pressurizing chamber 65 is pressurized. When the pressurized fuel pressure exceeds the opening pressure of the discharge valve 67, the discharge valve 67 is opened, and the fuel in the pressurizing chamber 65 is pumped to the common rail 1 through the high-pressure discharge path 9d.

  As a result, the high-pressure fuel is stored in the common rail 1. The high-pressure fuel stored in the common rail 1 is injected into each combustion chamber of the internal combustion engine from an injector 2 driven by a control signal from the ECU.

  Next, the operation of the feed pump 5 will be described. When the rotor 52 rotates, the four working chambers 55 move in the rotor rotation direction B with volume changes. Here, one working chamber 55 will be described as an example. If the working chamber 55 communicates with the suction port 511 in the process of increasing the volume of the working chamber 55, fuel flows into the working chamber 55 from the suction port 511. Subsequently, the communication between the working chamber 55 and the suction port 511 is blocked, the working chamber 55 is sealed, the volume of the working chamber 55 is reduced, and the fuel in the working chamber 55 is pressurized. Thereafter, the working chamber 55 and the discharge port 512 communicate with each other, and the pressurized fuel in the working chamber 55 is discharged to the discharge port 512.

  During operation of the feed pump 5, the blade 53 is urged toward the inner side in the rotor radial direction by the pressure of the front working chamber acting on the pressure receiving surface 532. Further, the blade 53 is urged outward in the rotor radial direction by the pressure of the rear working chamber acting on the rear end surface 533, the urging force of the spring 54, and the centrifugal force acting on the blade 53.

  By the way, when the vehicle is decelerated, for example, the target discharge amount of the high-pressure pump 6 becomes 0, and it is necessary to return all the fuel discharged from the feed pump 5 to the suction side of the feed pump 5. As described above, in the operation region where the target discharge amount of the high-pressure pump 6 is zero, the regulator valve 8 is first opened, and the fuel discharged from the feed pump 5 is returned to the suction side of the feed pump 5.

  If the feed pressure exceeds a predetermined pressure even when the regulating valve 8 is operating, the pressure in the front working chamber is increased, and the force for urging the blade 53 toward the inner side in the rotor radial direction is increased. . As a result, the force for urging the blade 53 toward the rotor radial inner side is larger than the force for urging the blade 53 toward the rotor radial inner side, and the blade 53 moves toward the rotor radial inner side. The sheet surface 531 of the blade 53 is separated from the inner peripheral surface of the housing 51. As a result, the rear working chamber and the front working chamber communicate with each other via a gap between the seat surface 531 of the blade 53 and the inner peripheral surface of the housing 51, the pump discharge efficiency is lowered, and the discharge pressure is lowered. The pressure difference between the working chamber and the rear working chamber is adjusted to a substantially constant value or less.

  In this way, in a situation where the feed pressure exceeds a predetermined pressure, the feed pump 5 self-adjusts the discharge pressure to reduce the discharge amount, so the fuel passage area in the regulator valve 8 is set smaller than before. can do. Therefore, the regulated valve 8 can be reduced in size.

  In the present embodiment, the regulating valve 8 is provided in order to control the feed pressure with high accuracy. However, the regulating valve 8 may be eliminated because the feed pump 5 self-adjusts the discharge pressure.

  In the above embodiment, the pressure receiving surface 532 of the blade 53 is formed over the entire drive shaft direction (hereinafter referred to as the blade width direction) of the blade 53. However, as in the first modification shown in FIG. The pressure receiving surface 532 of 53 may be formed only in a partial range in the blade width direction. In this case, since the area of the sheet surface 531 can be increased, the wear resistance of the sheet surface 531 is improved.

  In the above embodiment, the pressure in the rear working chamber is guided into the blade groove 521 by the slit 522 formed in the rotor 52. However, as in the second modification shown in FIG. 534 may be formed to guide the pressure in the rear working chamber into the blade groove 521. In this case, the processing is easier than when the slits 522 are formed in the rotor 52.

  Further, in the above embodiment, the pressure in the rear working chamber is guided into the blade groove 521 by the slit 522 formed in the rotor 52. However, as in the third modification shown in FIG. A hole 523 may be formed to guide the pressure in the rear working chamber into the blade groove 521. In this case, the processing is easier than when the slits 522 are formed in the rotor 52.

  Further, in the above embodiment, the pressure receiving surface 532 is inclined with respect to the tangent to the inner peripheral surface of the housing 51 so that the pressure receiving surface 532 and the seat surface 531 are continuous, but the fourth modification shown in FIG. As described above, the tip surface of the blade 53 may be stepped, and the boundary between the pressure receiving surface 532 and the seat surface 531 may be stepped. In this case, the pressure in the front working chamber is more likely to act on the entire area of the pressure receiving surface 532 than in the case where the pressure receiving surface 532 is inclined with respect to the tangent line of the inner peripheral surface of the housing 51. Operation is stable.

51 Housing 52 Rotor 53 Blade 55 Working chamber 521 Blade groove 531 Seat surface 532 Pressure receiving surface

Claims (6)

A housing (51) having a housing space formed therein, a rotor (52) disposed in the housing space and rotating, and a blade groove (521) of the rotor (52) being movable in the rotor radial direction. A plurality of blades (53) inserted and having a front end surface in contact with an inner peripheral surface of the housing (51) and a side surface in contact with a side surface of the housing (51);
The volume of the plurality of working chambers (55) surrounded by the inner peripheral surface of the housing (51), the side surface of the housing (51), the outer peripheral surface of the rotor (52), and the blade (53) is the rotor. In the vane pump that changes with the rotation of (52),
The pressure of the working chamber (55) located on the front surface of the blade (53) and the seat surface (531) in contact with the inner peripheral surface of the housing (51) on the front surface of the blade (53) in the rotor rotation direction. A vane pump comprising a pressure-receiving surface (532) on which the pressure acts.   A slit (522) for guiding the pressure of the working chamber (55) located on the rear side of the blade (53) in the rotor rotation direction into the blade groove (521) is formed in the rotor (52). The vane pump according to claim 1, wherein   A communication hole (523) for guiding the pressure of the working chamber (55) located on the rear side of the blade (53) in the rotor rotation direction into the blade groove (521) is formed in the rotor (52). The vane pump according to claim 1.   A slit (534) for guiding the pressure of the working chamber (55) located on the rear side of the blade (53) in the rotor rotation direction into the blade groove (521) is formed in the blade (53). The vane pump according to claim 1, wherein   The vane pump according to any one of claims 1 to 4, wherein the pressure receiving surface (532) is inclined with respect to a tangent to an inner peripheral surface of the housing (51).   The vane pump according to any one of claims 1 to 4, wherein a boundary portion between the seat surface (531) and the pressure receiving surface (532) is stepped.

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