JP3943852B2 - Pressure control valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure control valve, and more particularly, to a pressure control valve that is provided in a fuel tank of an automobile and controls a supply pressure of fuel pumped from the fuel tank to be constant.
[0002]
[Prior art]
In the fuel system of an automobile, the fuel in the fuel tank is pumped out and pumped to the fuel injection device. The fuel supply by the pump needs to have a constant pressure in order to ensure that the control in the fuel injection device is always performed properly, and for this purpose, a pressure control valve is used. This pressure control valve is generally provided in the middle of the piping from the pump to the fuel injection device, and returns the surplus fuel supplied at a supply pressure higher than the pressure to be controlled from the pump to the fuel tank. , Have pressure control.
[0003]
Such pressure control valves include a type provided in the engine room and a type provided in the fuel tank. Here, a configuration example of a pressure control valve of the type provided in the fuel tank will be described.
[0004]
FIG. 9 is a central longitudinal cross-sectional view showing a configuration example of a conventional pressure control valve.
The pressure control valve 100 includes a resin body 101, a ball 102 constituting a valve body, a compression coil spring 103 that urges the ball 102, a plug 104 constituting a valve seat on which the ball 102 is seated, A diaphragm 105 that senses the supply pressure of fuel pumped from the pump, a holder 106 that is fixed together with the diaphragm 105 by caulking the plug 104, one end is welded to the ball 102, and the other end is a ball. A shaft 107 formed in a shape, a compression coil spring 108 for urging the diaphragm 105 and the plug 104 in the direction of the ball 102 via the holder 106, and the compression coil spring 108 are accommodated, and the outer peripheral portion of the diaphragm 105 is caulked. And a housing 109 that is fixed to the body 101 by processing. The compression coil spring 103 that biases the ball 102 has a spring load that is sufficiently smaller than the compression coil spring 108 that biases the diaphragm 105.
[0005]
The housing 109 has a shaft receiving portion 110 that is smoothly recessed outwardly at the center of the top portion. Around the shaft receiving portion 110, a plurality of fuel discharge ports 112 are formed. Further, a fuel supply port 113 is formed at the lower end of the body 101 in the drawing, and the fuel supply port 113 passes through a passage 114 provided in the axial direction of the body 101 and is a space on the pressure receiving surface side of the diaphragm 105. Is communicated to.
[0006]
In the pressure control valve 100 having such a configuration, when no fuel is supplied to the fuel supply port 113, the plug 104 is brought into contact with the cylindrical stopper 111 and the ball 102 is connected to the plug 104 as shown in FIG. Is fully closed.
[0007]
Here, when the pump is operated and fuel supply pressure is received at the fuel supply port 113, the diaphragm 105 is displaced upward in the figure against the urging force of the compression coil spring 108, and accordingly the plug is plugged. The ball 102 seated by 104 and the compression coil spring 103 also moves upward in the figure.
[0008]
When the shaft 107 integrated with the ball 102 also rises and the upper end of the shaft 107 abuts against the bottom of the shaft receiving portion 110, the plug 104 further rises from here, leaving the ball 102. Away from the pressure control valve 100 begins to open. The plug 104 is separated from the ball 102 and stops at a position where the fuel supply pressure and the load of the compression coil spring 108 are balanced. Thereby, the fuel supplied from the fuel supply port 113 passes through the passage 114, passes between the end face of the cylindrical stopper 111 and the plug 104, and between the ball 102 and the plug 104 and the valve through which the shaft 107 is inserted. It enters the space surrounded by the housing 109 through the hole, and is discharged from there through the fuel discharge port 112 provided on the end face of the housing 109 and returned to the fuel tank.
[0009]
In this state, when the supply pressure of the fuel pumped from the pump is further increased, the plug 104 is separated from the ball 102, the valve opening is increased to decrease the fuel supply pressure, and the fuel supply pressure is decreased. 104 approaches the ball 102 and decreases the valve opening to increase the fuel supply pressure. In this way, the fuel supply pressure is kept constant.
[0010]
Here, the plug 104 which constitutes the valve portion of the pressure control valve 100 together with the ball 102 will be described.
FIG. 10 is a cross-sectional view showing an example of a conventional plug, wherein (A) shows a plug whose seating surface is processed into an R shape, and (B) shows a plug whose seating surface is processed into a C surface.
[0011]
In the plug used in the conventional pressure control valve 100, the seating surface on which the ball 102 is seated is, as shown in (A), the plug 104a processed into the R shape 115 or as shown in (B), A plug 104b machined on the C surface 116 is used. These plugs 104a and 104b are formed by drilling the valve hole and then cutting the R shape 115 and the C surface 116 with a lathe.
[0012]
[Problems to be solved by the invention]
However, in the conventional pressure control valve, since the seating surface of the plug is formed by cutting, cutting traces and flashes remain on the R-shaped portion and the C-surface portion of the seating surface, which is a sealing property with the ball. In addition to deteriorating the film, there is a problem that the crest portion of the processing mark is peeled off due to the contact of the ball and the sealing performance is further deteriorated.
[0013]
Moreover, in order to improve such sealing performance, the R-shaped portion and the C-surface portion of the seating surface may be mirror-polished to remove the cutting traces and flashes, but the processing cost increases. There was a point.
[0014]
The present invention has been made in view of these points, and an object of the present invention is to provide a pressure control valve having a plug with high sealing performance and low cost.
[0015]
[Means for Solving the Problems]
In the present invention, in order to solve the above problem, a body having a fuel supply port connected to a discharge side of a pump for pumping fuel, a housing having a fuel discharge port for discharging excess pressure fuel into the fuel tank, A diaphragm sandwiched between the body and the housing and receiving a supply pressure of fuel introduced from the fuel supply port, and a valve hole fixed in the center of the diaphragm and opened in the axial direction of the center. A plug having a valve seat on the fuel supply port side of the valve hole, a ball-shaped valve body disposed at a position facing the valve seat of the plug, one end fixed to the valve body, and the other end A shaft that extends through the valve hole of the plug and is loosely fitted in a receiving portion that is recessed in the end surface of the housing, and a urging force in a direction in which the valve body is seated on the valve seat of the plug. 1 In the pressure control valve that includes a compression coil spring and a second compression coil spring that urges the diaphragm toward the fuel supply port, and controls the supply pressure of fuel pumped from the pump to be constant, the plug is , after the valve body is form-machined in Sokatachi byte portion seated, have a said valve seat and coining the same ball and the valve body, the body, accommodating the valve body of the ball-like And a cylindrical stopper for restricting the amount of displacement of the diaphragm toward the fuel supply port by the urging force of the second compression coil spring by contact of the plug, the plug being the cylindrical shape stopper and a large cylindrical guide than the inner diameter in abutting side of at least the outer shape of the cylindrical stopper is provided a pressure control valve characterized that you have been integrally projects.
[0016]
According to such a pressure control valve, the valve seat portion of the plug, on which the ball-shaped valve element is seated, was machined by coin cutting with a complete bite shape. As a result, the surface on which the valve body is seated can be made a surface that does not leave any machining traces, and the coining process can be used to recess the seating surface into a curved surface that follows the spherical surface of the valve body. However, it is possible to provide a plug that is cheap and has a good sealing property, and therefore, an inexpensive pressure control valve can be provided. In addition, because the seal is located inside the plug and protected by the presence of the guide, even if the plug is placed with the seal side down on the work table, the seal unit is directly attached to the work table. In the middle of placing or transporting the plug, the sealing portion is not damaged, so that the sealing performance can be maintained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings, taking as an example a case where the embodiment is applied to a pressure control valve that is provided in a fuel tank and controls the supply pressure of fuel pumped from a pump to a constant level To do.
[0018]
FIG. 1 is a central longitudinal sectional view showing the structure of a pressure control valve according to the present invention, and FIG. 2 is a plan view of the pressure control valve.
A pressure control valve 1 according to the present invention includes a resin body 2, a ball 3 constituting a valve body, a compression coil spring 4 for urging the ball 3, a plug 5 constituting a valve seat, and a pressure feed from a pump. A diaphragm 6 that senses the supplied fuel pressure, a holder 7 that is fixed so as to be integrated with the diaphragm 6 by caulking the plug 5, one end is welded to the ball 3, and the other end is formed in a spherical shape A compressed coil spring 9 for urging the diaphragm 6 and the plug 5 in the direction of the ball 3 through the shaft 8 and the holder 7, and housing the compression coil spring 9, and caulking the outer peripheral portion of the diaphragm 6 to the body The housing 10 is fixed to the housing 2.
[0019]
Here, the diaphragm 6 is constituted by a rubber sheet 6a and a polyimide film 6b which are arranged in an overlapping manner. The rubber sheet 6a has a rib integrally projecting on the outer peripheral portion thereof, and the rib is fitted into a groove formed in a ring shape on the upper surface of the body 2, and the polyimide film 6b is formed by caulking of the housing 10. The rubber sheet 6a is prevented from falling off and the high pressure side space is sealed by being sandwiched between the body 2 and the housing 10. The polyimide film 6b placed on the rubber sheet 6a serves as a reinforcing material for the rubber sheet 6a. The polyimide film 6b is sandwiched between the body 2 and the housing 10 via the rubber sheet 6a. The pressure resistance can be improved. The compression coil spring 4 that biases the ball 3 has a spring load that is sufficiently smaller than the compression coil spring 9 that biases the diaphragm 6.
[0020]
The plug 5 receives the ball 3 and the compression coil spring 4 and contacts a cylindrical stopper 11 formed integrally with the body 2 so as to restrict the amount of displacement of the diaphragm 6 due to the biasing force of the compression coil spring 9. It touches. Further, a cylindrical guide 5 a is integrally projected on the outer periphery of the lower end surface of the plug 5. The guide 5a is tapered on the inner wall surface so that the inner diameter of the contact surface side with the cylindrical stopper 11 is slightly larger than the outer shape of the cylindrical stopper 11 and increases toward the lower end in the figure. As a result, when the plug 5 is assembled, the guide 5a functions to position the plug 5 on the axis of the body 2 only by placing the plug 5 on the cylindrical stopper 11, thereby improving the assembly workability.
[0021]
The housing 10 has a shaft receiving portion 12 that is smoothly recessed outwardly at the center of the top portion, and the bottom portion is formed to have the same curvature as the spherical shape at the tip of the shaft 8. When no fuel is supplied from the pump, as shown in FIG. 1, the plug 5 is brought into contact with the end surface of the opposing cylindrical stopper 11 by the compression coil spring 9, and the ball 3 is plugged by the compression coil spring 4. In this case, the shaft receiving portion 12 is configured to loosely fit the tip of the shaft 8. That is, even if the shaft 8 tilts around the ball 3, the tip thereof is locked to the inner wall of the shaft receiving portion 12 so that the shaft 8 does not fall further.
[0022]
Further, as shown in FIG. 2, three fuel discharge ports 13 are formed around the shaft receiving portion 12 in the illustrated example. Here, by forming the fuel discharge port 13, a thin connecting portion 14 is formed between the shaft receiving portion 12 and the fuel receiving port 13. This connection part 14 comprises the deformation | transformation site | part for set value adjustment. That is, when the diaphragm 6 receives the supply pressure of the fuel, it is displaced upward in the figure, and accordingly, the plug 5 and the ball 3 are raised, and the plug 5 is located when the tip of the shaft 8 comes into contact with the bottom of the shaft receiving portion 12. However, the set value at which the pressure control valve 1 starts to open is adjusted by pressing the shaft receiving portion 12 from the outside and pushing it in. In the adjustment of the set value, only the fragile connecting portion 14 is deformed, so that the outer peripheral portion of the upper end surface of the housing 10 is not deformed. For this reason, when connecting a pipe ahead, the outer peripheral part of the upper end surface can hold | maintain a flat surface, Therefore The sealing surface with a connection pipe can be comprised.
[0023]
The operation of the pressure control valve 1 having the above configuration will be described. First, when the pump is stopped and no fuel is supplied to the fuel supply port 15, as shown in FIG. 1, the diaphragm 6 that does not receive the fuel supply pressure is moved downward by the compression coil spring 9. The plug 5 is abutted against the end face of the cylindrical stopper 11. At this time, the ball 3 is seated on the plug 5 by the compression coil spring 4, closes the valve hole, and is fully closed as the pressure control valve 1.
[0024]
Here, when the pump is operated and the supply of fuel to the fuel supply port 15 is started, the diaphragm 6 receives the supply pressure of the fuel, and is displaced upward in the figure against the urging force of the compression coil spring 9. To go. As the diaphragm 6 is displaced, the plug 5 also moves upward in the drawing, and the ball 3 biased by the compression coil spring 4 also moves upward in the drawing while being seated on the plug 5.
[0025]
As the ball 3 moves upward in the figure, the shaft 8 integrated therewith also rises. At this time, since the diaphragm 6 is not displaced in the horizontal posture, the plug 5 leaving the cylindrical stopper 11 is inclined. When the plug 5 is inclined, the shaft 8 fixed to the ball 3 seated on the plug 5 is also inclined. However, since the upper end of the shaft 8 is restricted by the inner wall surface of the shaft receiving portion 12, the shaft 8 is Pivot around. At this time, since the ball 3 has a spherical shape, the valve closed state is maintained regardless of the pivot position of the ball 3. That is, the ball 3 follows the valve seat of the plug 5 and keeps the valve closed state.
[0026]
When the plug 5 further rises, the shaft 8 fixed to the ball 3 also rises. At this time, the tip of the spherical shaft 8 rises while sliding along the inner wall surface of the shaft receiving portion 12. I will do it.
[0027]
And if the front-end | tip of the shaft 8 contact | abuts to the bottom part of the shaft receiving part 12 formed in the same curvature, the shaft 8 will no longer be able to raise with the plug 5. FIG. When the plug 5 further rises from here, the ball 3 is left in place, so that the plug 5 moves away from the ball 3. That is, the pressure control valve 1 starts to open. The starting position of the valve opening is a position where the upper end of the shaft 8 contacts the bottom of the shaft receiving portion 12, and this position is adjusted by deforming and moving the shaft receiving portion 12 inward in the axial direction.
[0028]
When the ball 3 is separated from the plug 5, the ball 3 and the shaft 8 urged by the compression coil spring 4 can swing around the spherical portion at the tip thereof.
When the fuel supply pressure is further increased, the diaphragm 6 is displaced upward in the figure, and the plug 5 is lifted so that the plug 5 is separated from the ball 3 and the fuel supply pressure and the load of the compression coil spring 9 are reduced. The plug 5 stops at the balanced position. As a result, the fuel supplied from the fuel supply port 15 passes through the passage 16, passes between the end face of the cylindrical stopper 11 and the plug 5, and passes between the ball 3 and the plug 5 and the shaft 8. It enters the space surrounded by the housing 10 through the hole, and is discharged from there through the fuel discharge port 13 provided on the end face of the housing 10.
[0029]
When the supply pressure of the fuel pumped from the pump is further increased, the diaphragm 6 is displaced upward in the figure, and the plug 5 is separated from the ball 3 to increase the valve opening, so that the flow rate through the pressure control valve 1 is increased. Increases the fuel supply pressure. On the other hand, when the fuel supply pressure is lowered, the diaphragm 6 is displaced downward in the drawing, the plug 5 approaches the ball 3 and the valve opening is reduced, so that the flow rate through the pressure control valve 1 is reduced. Increase fuel supply pressure. In this way, the fuel supply pressure is kept constant.
[0030]
FIG. 3 is a cross-sectional view showing details of the plug.
The valve seat on which the ball 3 is seated on the plug 5 includes a line 21 extending parallel to the axis of the valve hole 5b along the inner wall of the valve hole 5b through which the shaft 8 passes, and a surface including the end face on the side where the ball 3 is disposed. A line 21 and an end surface extending along the inner wall of the valve hole 5b through a position separated by a predetermined distance from the intersection with the valve hole 5b on the discharge side and radially outside of the valve hole 5b, in the illustrated example, 0.5 mm. In the illustrated example, the lines 22 and 24 are inclined at a predetermined angle with respect to the plane 22 to be included, and in the illustrated example, extend inwardly by 2 to 10 °, and the intersections of the inclined lines 23 and 24 are formed. Has a cross-sectional contour shape composed of an R shape with a curvature radius of 0.3 mm.
[0031]
Such a valve seat is formed by carrying out a total shape cutting using the total shape bite which has the above contour shapes. Here, the position where the line 21 extending along the inner wall of the valve hole 5b and the inclined line 23 intersect, and the position where the surface 22 including the end surface of the plug 5 and the inclined line 24 intersect, that is, the inner wall and the processed end of the end surface. Is set at a position away from the seal portion formed by the valve seat and the ball 3. The angles of the inclined lines 23 and 24 are set as small as possible when it is desired to make the flow rate characteristics of the pressure control valve 1 substantially the same as the conventional one.
[0032]
Next, the processing procedure of the plug 5 will be described with reference to FIGS.
4 is an enlarged partial cross-sectional view of the main part of the plug showing the state before the valve seat machining, FIG. 5 is an enlarged partial cross-sectional view of the main part of the plug showing the state before the total cutting, and FIG. FIG. 7 is an enlarged partial cross-sectional view of the main part of the plug showing the state before coining, and FIG. 8 is an enlarged partial cross-sectional view of the main part of the plug showing the state after coining. is there.
[0033]
First, in a state of cutting with a cutting tool, as shown in FIG. 4, cutting traces remain on the inner wall surface of the valve hole 5 b of the plug 5 and the end surface on the side where the ball 3 is disposed.
[0034]
Next, the total cutting is performed using the total cutting tool 31 having the cross-sectional contour shape of the valve seat described in FIG. As shown in FIG. 5, this processing is performed by sending the total form bit 31 to the position of the broken line in the figure. Here, the positions 32 and 33 indicate the machining end portions of the machining area formed by the overall cutting tool 31. Thereby, as shown in FIG. 6, the plug 5 is processed so that the valve seat serving as the seal portion does not have a processing mark.
[0035]
Next, coining is performed using the balls 3. As shown in FIG. 7, this processing is performed by applying a load to the ball 3 in a state where the ball 3 is in contact with the valve seat, and sending the ball 3 to the broken line position in the figure. Accordingly, as shown in FIG. 8, the plug 5 can form the seating surface 5c that is recessed in the spherical shape by deforming the valve seat serving as the seal portion following the spherical shape of the ball 3. Thereby, the seal part formed by contact | abutting with the plug 5 and the ball | bowl 3 becomes a surface contact from the conventional line contact, and can improve a sealing performance. In addition, since the coining process is performed after the cutting trace is erased by the overall shape cutting process, fine metal peeling from the cutting trace does not occur by the coining process.
[0036]
【The invention's effect】
As described above, in the present invention, the valve seat portion on which the ball is seated is configured to use a plug that has been cut into a full shape with a full bite and coined with the ball. Thereby, since a processing trace does not remain in the seal portion, the sealing performance after the coining process is improved, and polishing for removing the processing trace is not required, so that the cost can be reduced.
[0037]
In addition, it is possible to eliminate the flash and cutting traces in the seal part by taking a wide processing area of the total tool and separating the processing end part from the seal part, thus eliminating the deterioration factor of the sealing performance. .
[0038]
Furthermore, by providing the guide on the fuel supply pressure introduction side end face of the plug, the plug can be easily positioned at the axial position of the body at the time of assembling the plug, so that the assembling workability can be improved. In addition, because the seal is located inside the plug and protected by the presence of the guide, even if the plug is placed with the seal side down on the work table, the seal unit is directly attached to the work table. There is no contact with. Accordingly, the seal portion is not damaged during the placement or transportation of the plug, and the sealing performance can be maintained.
[Brief description of the drawings]
FIG. 1 is a central longitudinal sectional view showing a configuration of a pressure control valve according to the present invention.
FIG. 2 is a plan view of a pressure control valve.
FIG. 3 is a cross-sectional view showing details of a plug.
FIG. 4 is an enlarged partial cross-sectional view of a main part of the plug showing a state before the valve seat is processed.
FIG. 5 is an enlarged partial cross-sectional view of a main part of the plug showing a state before the total shape cutting.
FIG. 6 is an enlarged partial cross-sectional view of a main part of the plug showing a state after the total cutting.
FIG. 7 is an enlarged partial cross-sectional view of a main part of the plug showing a state before coining.
FIG. 8 is an enlarged partial cross-sectional view of a main part of the plug showing a state after coining.
FIG. 9 is a central longitudinal section showing a configuration example of a conventional pressure control valve.
10A and 10B are cross-sectional views showing an example of a conventional plug, wherein FIG. 10A shows a plug whose seating surface is processed into an R shape, and FIG. 10B shows a plug whose seating surface is processed into a C surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure control valve 2 Body 3 Ball 4 Compression coil spring 5 Plug 5a Guide 5b Valve hole 5c Seating surface 6 Diaphragm 6a Rubber sheet 6b Polyimide film 7 Holder 8 Shaft 9 Compression coil spring 10 Housing 11 Cylindrical stopper 12 Shaft receiving part 13 Fuel Discharge port 14 Connecting portion 15 Fuel supply port 16 Passage 31 Total form bite

Claims (2)

A body having a fuel supply port connected to a discharge side of a pump for pumping fuel, a housing having a fuel discharge port for discharging excess pressure fuel into a fuel tank, and the fuel held by the body and the housing A diaphragm that is displaced by receiving a supply pressure of fuel introduced from a supply port, and a valve hole that is fixed to the center of the diaphragm and that is opened in the axial direction of the center, the valve hole side of the fuel supply port A plug having a valve seat, a ball-shaped valve body disposed at a position facing the valve seat of the plug, one end fixed to the valve body, and the other end extending through the valve hole of the plug. A shaft loosely fitted in a receiving portion recessed in the end face of the housing, a first compression coil spring for urging the valve body in a direction for seating on the valve seat of the plug, and the diaphragm In the pressure control valve, wherein a second compression coil spring for urging the side of the fuel supply port, to control the supply pressure of the fuel pumped from the pump constant,
It said plug, after the valve body is form-machined in Sokatachi byte portion seated, have a said valve seat and coining the same ball and the valve body,
The body accommodates the ball-shaped valve body and regulates the amount of displacement of the diaphragm toward the fuel supply port by the bias of the second compression coil spring by contact of the plug. has Jo stopper, said plug, the pressure the cylindrical stopper and large cylindrical guide than the inner diameter in abutting side of at least the outer shape of the cylindrical stopper is characterized that you have been integrally projecting Control valve.   The valve seat of the plug is an intersection of a line extending parallel to the axis of the valve hole along the inner wall of the valve hole through which the shaft passes and a surface including an end surface on the side where the ball-shaped valve body is disposed. Extending to the discharge side of the valve hole and radially outward from the surface including the end surface and a line extending along the inner wall of the valve hole through a position separated by a predetermined distance. The pressure control valve according to claim 1, wherein the pressure control valve has a cross-sectional contour shape including an inclined line and an R shape formed at a portion forming an intersection of the inclined lines.

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