JP5531569B2 - pump - Google Patents

Description

  The present invention relates to a pump that sucks and discharges fluid.

  A fuel injection device for injecting fuel into a compression ignition type internal combustion engine includes a supply pump that pressurizes the fuel and supplies it to a common rail. In the supply pump, the plunger reciprocates in the plunger hole in the cylindrical space formed in the cylinder to pressurize the fuel, and the pressurized fuel is supplied to the common rail side through the discharge hole formed in the cylinder. It is designed to be discharged. Since there is a possibility that stress concentrates at the intersection between the plunger hole and the discharge hole and the cylinder is damaged, an elliptical counterbore is provided at the intersection to disperse the stress (for example, patents) Reference 1).

JP 2009-68371 A

  However, in order to realize further low emission, a high pressure is required for the fuel injection device. Therefore, it is necessary to further increase the pressure resistance of the cylinder.

  In view of the above points, an object of the present invention is to increase the pressure resistance of a cylinder in a pump having a configuration in which a plunger hole and a discharge hole intersect.

In order to achieve the above object, in the first aspect of the present invention, the plunger hole (13a) of the cylindrical space formed in the cylinder (13) and the cylinder (13) are formed more than the plunger hole (13a). A plunger hole (13c) located on the radially outer side of the plunger hole and having one end intersecting the plunger hole (13a); and a plunger (14) that reciprocates in the plunger hole (13a) to pressurize the fluid. 14) In the pump in which the fluid pressurized in 14) is guided to the outside through the discharge hole (13c), the cylinder (13) has a plunger at the intersection of the plunger hole (13a) and the discharge hole (13c). A counterbore part (13d) recessed toward the outer side in the hole diameter direction is provided. When the counterbore part (13d) is viewed from the center of the plunger hole diameter direction, the plunger hole (13a) and the counterbore part ( Of the boundary portions (13e, 13f) with respect to 3d), the first boundary portions (13e) located on both sides in the plunger hole axial direction of the discharge holes (13c) extend linearly in a direction perpendicular to the plunger hole axis. In addition, the linear first boundary portion (13e) is formed to be longer than the diameter of the discharge hole (13c), and the second boundary portion (on the both sides in the circumferential direction of the plunger hole of the discharge hole (13c)) ( 13f) is arcuate, and when the counterbore part (13d) is viewed from the center in the plunger hole radial direction, the linear first boundary part (13e) and the arcuate second boundary part (13f) It has an elongated hole shape that is long in the direction perpendicular to the hole axis, and includes boundary portions (13e, 13f) between the plunger hole (13a) and the counterbore portion (13d), and the discharge hole (13c) and the counterbore portion ( 13d) and the boundary (13h) Characterized in that the chamfered.

  According to this, since the first boundary portion (13e) extends in a direction perpendicular to the plunger hole axis (that is, in the same direction as the stress), the first boundary portion (13e) has a stress concentration factor of 1 (that is, a minimum). ), The stress generated in the vicinity of the first boundary portion (13e) is reduced, and the pressure resistance of the cylinder (13) can be increased in the pump configured to intersect the plunger hole (13a) and the discharge hole (13c). it can.

In the invention described in claim 1, when viewed counterbored portion (13d) from the plunger hole diameter direction center, a boundary portion of the plunger hole and (13a) countersunk portion and (13d) (13e, 13f) of the discharge The 2nd boundary part (13f) located in the plunger hole circumferential direction both sides of a hole (13c) is circular, It is characterized by the above-mentioned.

  By the way, when both the 1st boundary part (13e) and the 2nd boundary part (13f) are straight lines, the connection part of both boundary parts (13e, 13f) becomes a corner | angular part shape, and both boundary parts (13e, 13f), stress concentrates on the connecting part, but by making the second boundary part (13f) arc-shaped, the connecting part of both boundary parts (13e, 13f) becomes R-shaped, and both boundary parts (13e) , 13f), the stress concentration on the connecting portion can be relaxed.

In the invention described in claim 1, the boundary portion of the flop plunger hole and (13a) countersunk portion and (13d) (13e, 13f) , and the boundary portion of the discharge hole and (13c) counter bore and (13d) ( 13h) is characterized by chamfering.

  According to this, stress concentration on each boundary portion (13e, 13f, 13h) can be relaxed.

  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 sectional drawing which shows the structure of the pump which concerns on one Embodiment of this invention. (A) is sectional drawing which shows the principal part of the cylinder 13 in the pump of FIG. 1, (b) is sectional drawing which follows the AA line of (a), (c) is along the BB line of (a). It is sectional drawing.

  An embodiment of the present invention will be described. The pump according to the present embodiment is used as a supply pump for supplying high-pressure fuel to a common rail that stores high-pressure fuel in a fuel injection device for injecting fuel into a compression ignition internal combustion engine.

  FIG. 1 shows a configuration of a pump according to the present embodiment. A pump housing 10 includes a cam chamber 10a located on the lower end side thereof, and a cylindrical space extending from the cam chamber 10a toward the upper side of the pump housing 10. And a cylinder insertion hole 10c in a columnar space extending from the slider insertion hole 10b to the upper end surface of the pump housing 10 are formed.

  A cam shaft 11 driven by a compression ignition type internal combustion engine (hereinafter referred to as an internal combustion engine) (not shown) is disposed in the cam chamber 10 a, and the cam shaft 11 is rotatably supported by the pump housing 10. A cam 12 is formed on the cam shaft 11.

  A cylinder 13 is attached to the cylinder insertion hole 10c so as to close the cylinder insertion hole 10c. The cylinder 13 is formed with a plunger hole 13a having a columnar space, and a columnar plunger 14 is inserted into the plunger hole 13a so as to freely reciprocate. A pump chamber 15 is formed by the upper end surface of the plunger 14 and the inner peripheral surface of the cylinder 13.

  A sheet 14 a is connected to the lower end of the plunger 14, and the sheet 14 a is pressed against the slider 17 by a spring 16. The slider 17 is formed in a bottomed cylindrical shape, and is inserted into the slider insertion hole 10b so as to reciprocate. A cam roller 18 is rotatably attached to the slider 17, and the cam roller 18 is in contact with the cam 12. When the cam 12 is rotated by the rotation of the cam shaft 11, the plunger 14 is driven to reciprocate together with the sheet 14a, the slider 17 and the cam roller 18.

  A fuel reservoir 19 is formed between the cylinder 13 and the pump housing 10. Low pressure fuel discharged from a feed pump (not shown) is supplied to the fuel reservoir 19 via a low pressure fuel pipe (not shown). Further, the fuel reservoir 19 can communicate with the pump chamber 15 via a suction passage 13 b formed in the cylinder 13 and a suction passage 31 a in the electromagnetic valve 30.

  A discharge hole 13c is formed in the cylinder 13 on the outer side in the plunger hole radial direction than the plunger hole 13a. One end of the discharge hole 13 c intersects with the plunger hole 13 a and is always in communication with the pump chamber 15. The pump chamber 15 is connected to a common rail (not shown) via the discharge hole 13c, the discharge valve 20, and a high pressure fuel pipe (not shown).

  The discharge valve 20 is attached to the cylinder 13 on the downstream side of the discharge hole 13c. The discharge valve 20 includes a valve body 20a that opens and closes the discharge hole 13c, and a spring 20b that biases the valve body 20a in the valve closing direction. The fuel pressurized in the pump chamber 15 moves the valve body 20a in the valve opening direction against the urging force of the spring 20b and is pumped to the common rail.

  The electromagnetic valve 30 is screwed and fixed to the cylinder 13 so as to close the pump chamber 15 at a position facing the upper end surface of the plunger 14. The body 31 of the solenoid valve 30 is formed with a suction passage 31a having one end communicating with the pump chamber 15 and the other end communicating with the suction passage 13b, and a seat portion (not shown) disposed in the suction passage 31a. Has been.

  The solenoid valve 30 moves integrally with a solenoid 32 that generates a suction force when energized, an armature 33 that is attracted by the solenoid 32, a spring 34 that urges the armature 33 toward the opposite suction side, and the armature 33. The valve body 35 opens and closes the suction passage 31a by contacting and separating from the seat portion, and the stopper 36 regulates the position of the valve body 35 when the valve is opened. The stopper 36 is sandwiched between the body 31 of the electromagnetic valve 30 and the cylinder 13, and has a large number of communication holes (not shown) that allow the suction passage 31 a and the pump chamber 15 to communicate with each other.

  Next, the structure of the principal part of the pump which becomes this embodiment is explained in full detail. 2A is a cross-sectional view showing a main part of the cylinder 13 in the pump of FIG. 1, FIG. 2B is a cross-sectional view taken along the line AA of FIG. 2A, and FIG. It is sectional drawing which follows the BB line of (a).

  As shown in FIG. 2, a portion of the discharge hole 13c close to the plunger hole 13a is orthogonal to the plunger hole axis J1.

  A counterbore portion 13d that is recessed from the inner peripheral surface of the cylinder 13 toward the radially outer side of the plunger hole so as to surround the discharge hole 13c at an intersecting portion of the inner peripheral surface of the cylinder 13 where the plunger hole 13a and the discharge hole 13c intersect. Is provided.

  When the counterbore part 13d is viewed from the center in the plunger hole radial direction with the plunger hole 13a in front (see FIG. 2A), the plunger hole of the discharge hole 13c is a boundary part between the plunger hole 13a and the counterbore part 13d. The first boundary portions 13e located on both sides in the axis J1 direction extend linearly in a direction perpendicular to the plunger hole axis J1. Here, c> d, where c is the distance between the two first boundary portions 13e and d is the inner diameter of the discharge hole 13c.

  Further, when the counterbore part 13d is viewed from the center in the plunger hole radial direction, the plunger hole circumferential direction of the discharge hole 13c in the boundary part between the plunger hole 13a and the counterbore part 13d (the left-right direction in FIG. 2A). The second boundary portion 13f located on both sides has a circular arc shape that protrudes outward in the circumferential direction of the plunger hole.

  Furthermore, an inclined surface 13g inclined with respect to the axis of the discharge hole 13c is formed between the first boundary portion 13e and the discharge hole 13c in the counterbore portion 13d. The inclined surface 13g is inclined so as to gradually approach the axis of the discharge hole 13c from the inner peripheral surface of the cylinder 13 toward the radially outer side of the plunger hole.

  The counterbore 13d is formed by cutting (for example, milling). When the cutting process is completed, the first boundary portion 13e, the second boundary portion 13f, and the third boundary portion 13h between the discharge hole 13c and the spot facing portion 13d are in an edge shape. Therefore, in the present embodiment, electrolytic processing is performed after cutting to melt and remove the edge portions of the first boundary portion 13e, the second boundary portion 13f, and the third boundary portion 13h, and the boundary portion 13e. , 13f, 13h are chamfered.

  The operation of the pump configured as described above will be described. First, when the solenoid 32 of the electromagnetic valve 30 is not energized, the valve element 35 is moved to the valve open position by the urging force of the spring 34. That is, the valve body 35 is separated from the seat portion of the body 31, and the suction passage 31a is opened.

  When the plunger 14 is lowered while the suction passage 31a is opened, the low-pressure fuel discharged from the feed pump is transferred to the pump chamber 15 via the fuel reservoir 19, the suction passage 13b, and the suction passage 31a. Supplied.

  Next, when the plunger 14 starts to rise, the plunger 14 tries to pressurize the fuel in the pump chamber 15. However, since the solenoid valve 30 is not energized and the suction passage 31a is opened at the beginning of the upward movement of the plunger 14, the fuel in the pump chamber 15 passes through the suction passage 31a and the suction passage 13b. It overflows to the reservoir 19 side and is not pressurized.

  When the solenoid valve 30 is energized during the overflow of fuel in the pump chamber 15, the armature 33 and the valve body 35 are sucked against the spring 34, and the valve body 35 is seated on the seat portion of the body 31. The suction passage 31a is closed. Thereby, the overflow of the fuel to the fuel reservoir 19 side is stopped, and pressurization of the fuel in the pump chamber 15 by the plunger 14 is started. The discharge valve 20 is opened by the fuel pressure in the pump chamber 15, and the fuel is pumped to the common rail.

  Next, the tensile stress generated on the inner peripheral surface of the cylinder 13 will be described in detail. Due to the pressure of the fuel pressurized by the plunger 14, a force acts on the cylinder 13 so as to expand the cylinder 13 in the plunger hole diameter direction, and a stress is generated in the cylinder 13. The direction of the stress is the circumferential direction of the plunger hole (in other words, the direction perpendicular to the plunger hole axis J1 when the cylinder 13 is expanded).

  Here, the first boundary 13e extends in a direction perpendicular to the plunger hole axis J1, that is, in the same direction as the stress. In this case, since the stress concentration coefficient of the first boundary portion 13e is 1 (that is, the minimum), the stress generated in the vicinity of the first boundary portion 13e is reduced, and the pressure resistance strength of the cylinder 13 can be increased.

  When both the first boundary portion 13e and the second boundary portion 13f are straight lines, the connection portion between both the boundary portions 13e and 13f has a corner shape, and stress is applied to the connection portion between both the boundary portions 13e and 13f. Whereas the second boundary portion 13f has an arc shape, the connecting portion between both the boundary portions 13e and 13f becomes an R shape, and stress concentration on the connecting portion between both the boundary portions 13e and 13f is reduced. Can do.

  Furthermore, since the first boundary portion 13e, the second boundary portion 13f, and the third boundary portion 13h are chamfered, stress concentration on the boundary portions 13e, 13f, and 13h can be reduced.

  From the viewpoint of avoiding stress concentration near the first boundary portion 13e and the second boundary portion 13f, the counterbore portion 13d is about 180 degrees in the plunger hole circumferential direction with the position of the plunger hole 13a as the center. It is desirable to provide in the range. Similarly, from the viewpoint of avoiding stress concentration near the first boundary portion 13e, it is desirable that the dimensional difference between the distance c and the inner diameter d is small.

(Other embodiments)
In the above embodiment, the present invention is applied to a supply pump of a fuel injection device for an internal combustion engine. However, the present invention can be widely applied to a pump that sucks and discharges fluid.

  Moreover, in the said embodiment, although the site | part close | similar to the plunger hole 13a among the discharge holes 13c is orthogonal to the plunger hole axis J1, the site | part close | similar to the plunger hole 13a among the discharge holes 13c, or the whole discharge hole 13c. However, the present invention can also be applied to a pump that is inclined with respect to the plunger hole axis J1.

13 Cylinder 14 Plunger 13a Plunger hole 13c Discharge hole 13d Counterbore part 13e First boundary part 13f Second boundary part

Claims (1)

A plunger hole (13a) in a cylindrical space formed in the cylinder (13);
A discharge hole (13c) formed in the cylinder (13), located on the radially outer side of the plunger hole than the plunger hole (13a) and having one end intersecting the plunger hole (13a);
A plunger (14) that reciprocates in the plunger hole (13a) to pressurize the fluid,
In the pump in which the fluid pressurized by the plunger (14) is guided to the outside through the discharge hole (13c),
The cylinder (13) is provided with a counterbore (13d) that is recessed toward the radially outer side of the plunger hole at the intersection of the plunger hole (13a) and the discharge hole (13c).
When the counterbore part (13d) is viewed from the center in the plunger hole radial direction, among the boundary parts (13e, 13f) between the plunger hole (13a) and the counterbore part (13d), the discharge hole (13c) First boundary portions (13e) located on both sides of the plunger hole axial direction extend linearly in a direction perpendicular to the plunger hole axial line, and the linear first boundary portion (13e) is the discharge hole. It is formed longer than the diameter of (13c),
Second boundary portions (13f) located on both sides in the circumferential direction of the plunger hole of the discharge hole (13c) are arcuate,
When the counterbore part (13d) is viewed from the center in the plunger hole radial direction, the linear first boundary part (13e) and the arcuate second boundary part (13f) are located with respect to the plunger hole axis. Has a long hole shape in the vertical direction,
Chamfering is present at the boundary portions (13e, 13f) between the plunger hole (13a) and the counterbore portion (13d) and at the boundary portion (13h) between the discharge hole (13c) and the counterbore portion (13d). A pump characterized by being applied.

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