JPH03182679A - Pressure regulating valve for fuel injection pump - Google Patents

Abstract

PURPOSE:To improve adhesion between a valve body and a seal part and perpendicularity of a coil spring by forming an uneven surface with a second valve body containing chamber in a first valve body and a second valve body and sliding the protrusion part of the second valve body in a recessed part. CONSTITUTION:A recessed part 24 is formed in the bottom part of a valve body containing chamber 17 of a first valve body 13 and a guide hole 25 is formed. A ball valve body 20 forming a second valve body is contained in the containing chamber 17 in a state to be supported by a spring support member 21. A coil spring member 22 is disposed to the spring support member 21 and a through-hole 18 of a plug body 19 is closed with a valve body 20. A slide part 26 being a protrusion part and slid with the recessed part 24 is formed on the lower end part of the spring support member 21, and a guide rod 27 slid within the guide hole 25 is formed to the lower end of the recessed part. This constitution causes movement of the spring support member 21 in a state to hold a vertical state, always adheres the valve body 20 to a seal part and holds the spring 22 in a vertical state, and improves reliability.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a pressure valve used in a fuel injection pump for a diesel engine and installed between a pressurizing chamber of the fuel injection pump and a fuel injection nozzle, The pressure inside the pipe between the pressurizing chamber of the fuel injection pump and the fuel injection nozzle at the end of injection (
This invention relates to a pressure regulating valve that can set residual pressure to a predetermined pressure.

[Conventional technology]

In recent years, environmental pollution caused by the noise and exhaust gas of diesel vehicles has become a social problem, and high injection pressure has become an essential requirement for fuel injection pumps to reduce exhaust gas. Therefore, current efforts are being made to increase the injection pressure of conventional pumps by increasing the cam speed, making the nozzle injection hole smaller, etc. However, the disadvantages of increasing the injection pressure are secondary injection and cavitation, and as a way to overcome these disadvantages, a pressure regulating valve (constant residual pressure valve) as shown in Japanese Patent Application Laid-Open No. 60-119366 ) is required. That is, a first valve body is provided that supplies fuel from the pressurizing chamber (plunger chamber) of the fuel injection pump to the fuel injection nozzle against the spring force, and a valve body is provided that resists the spring force of the coil spring in the first valve body. A second valve body is provided for returning fuel from the fuel injection nozzle to the pressurizing chamber of the fuel injection pump.

[Problem to be solved by the invention]

However, due to the high energy of the reflected waves from the nozzle, a high load is applied to the coil spring of the second valve body, and the lift amount of the coil spring becomes larger than expected, which deteriorates the responsiveness of the second valve body and causes the coil spring of the second valve body to become larger than expected. There was a risk that the constant residual pressure, which is a function, could not be maintained and performance would deteriorate.

In addition, when assembling the coil spring of the second valve body, if the coil spring is assembled in a state where it has fallen down, the adhesion of the sealing part may deteriorate and reliability may decrease, or the coil spring assembly may be damaged. The attachment will be applied later during operation.
The high energy of the reflected waves from the nozzle places a high load on the coil spring of the second valve body, causing the spring to fall over a large amount, which may cause interference with other parts on the outer periphery of the coil spring, resulting in a decrease in performance. There was that.

An object of the present invention is to provide a pressure regulating valve for a fuel injection pump that can improve performance and reliability due to the biasing means of the second valve body.

[Means to solve the problem]

The first invention is provided in a fuel passage between a pressurizing chamber of a fuel injection pump and a fuel injection nozzle, and injects fuel from the pressurizing chamber of the fuel injection pump against the urging force of the first urging means. A first valve body that supplies fuel to the nozzle, and a second biasing means that is provided in a valve body storage chamber in the first valve body, and that allows application of the fuel injection pump from the fuel injection nozzle against the biasing force of a second biasing means. A pressure regulating valve for a fuel injection pump comprising a second valve body that returns fuel to a pressure chamber, wherein the valve body storage chamber and the second valve body form an uneven part, and the convex part is a second valve body. The gist of this invention is a pressure regulating valve for a fuel injection pump in which the valve body slides within a recess as the valve body moves.

The second invention is provided in a fuel passage between a pressurizing chamber of a fuel injection pump and a fuel injection nozzle, and the fuel is transferred from the pressurizing chamber of the fuel injection pump to the fuel injection nozzle against the urging force of the urging means. a first valve body that supplies fuel, and a first valve body that is provided in a valve body storage chamber in the first valve body and returns fuel from the fuel injection nozzle to the pressurizing chamber of the fuel injection pump against the biasing force of a coil spring. A pressure regulating valve for a fuel injection pump comprising two valve bodies, wherein a guide portion for moving the second valve body only in a predetermined direction is formed in the valve body storage chamber or the second valve body. The gist is a pressure regulating valve for injection pumps.

A third invention is provided in a fuel passage between a pressurizing chamber of a fuel injection pump and a fuel injection nozzle, and the fuel is transferred from the pressurizing chamber of the fuel injection pump to the fuel injection nozzle against the urging force of the urging means. a first valve body that supplies fuel, and a first valve body that is provided in a valve body storage chamber in the first valve body and returns fuel from the fuel injection nozzle to the pressurizing chamber of the fuel injection pump against the biasing force of a coil spring. The gist of the pressure regulating valve for a fuel injection pump is a pressure regulating valve for a fuel injection pump having a valve body having a fixing part for fixing an end of the coil spring in the valve body storage chamber. It is something to do.

[Effect]

In the first invention, the second invention is caused by the reflected wave from the fuel injection nozzle.
The second valve element opens against the urging force of the urging means, and the fuel is returned to the pressurizing chamber of the fuel injection pump.
With the movement of the second valve body, the convex portion slides within the concave portion and functions as a dashpot, thereby suppressing excessive movement of the second valve body.

In the second invention, the second valve element opens against the biasing force of the coil spring due to the reflected wave from the fuel injection nozzle, and the fuel is returned to the pressurizing chamber of the fuel injection pump. This allows the second valve body to move only in a predetermined direction, thereby preventing the coil spring from falling.

In the third invention, the second valve element opens against the biasing force of the coil spring due to the reflected wave from the fuel injection nozzle, and the fuel is returned to the pressurizing chamber of the fuel injection pump. Since the end is fixed, it is prevented from falling over.

[First Embodiment] An embodiment embodying the present invention will be described below with reference to the drawings.

FIG. 1 shows a pressure regulating valve 2 for a fuel injection pump provided on the discharge side of a Bosch type fuel injection pump l.
FIG. 2 shows a cross section of the main part of the pressure regulating valve 2. As shown in FIG.

A mounting groove 5 is formed in the pump housing 3 of the fuel injection pump 1 and communicates with a plunger chamber 4 as a pressurizing chamber, and a pedestal 6 is disposed within the mounting groove 5. Further, a through hole 7 is formed in this pedestal 6. Further, a valve housing 8 is screwed into the mounting groove 5 , and a recess 9 that opens into the through hole 7 of the base 6 is formed in the valve housing 8 .

Further, a communication hole 1o is formed in the valve housing 8 and communicates with the recess 9, and a fuel injection nozzle 12 is connected to the communication hole 10 via a pipe 11.

A first valve body 13 is disposed within the recess 9, and the first valve body 13 has a conical portion 13a at its center and a guide portion 13b at its lower end. The guide portion 13b of the first valve body 13 slides within the through hole 7 of the base 6. Also, within the recess 9, the valve body stopper 14 and the conical portion 13 of the first valve body 13
A coil spring 15 as a first biasing means is disposed between the coil spring 15 and the first biasing means.
A valve body 13 is seated on a valve seat 16.

A valve body storage chamber 17 is formed within the first valve body 13, and a plug body 19 having a through hole 18 is press-fitted and fixed into the valve body housing chamber 17. Further, a ball valve body 20 constituting a second valve body is disposed within the valve body storage chamber 17, and a spring bearing of this ball valve body 20 constituting the second valve body is supported by a member 21. . A coil spring 22 as a second biasing means is disposed in the spring receiver member 21, and the ball valve body 20 closes the through hole 18 of the plug body 19 by the coil spring 22.

The first valve body 13 is provided with a communication hole 23 that communicates with the valve body storage chamber I7 and the plunger chamber 4 of the fuel injection pump 1 when the first valve body 13 is seated. Also, the first valve body 1
A recess 24 is formed at the bottom of the valve body storage chamber 17 of No. 3, and a guide hole 2 as a guide is formed at the bottom of the recess 24.
5 extends downward. Further, the spring receiver has a sliding portion 26 at the lower end of the member 21 as a convex portion that slides inside the recessed portion 24.
Further, a guide rod 27 is formed at the lower end of the sliding portion 26 as a guide portion that slides within the guide hole 25 .

Here, the inner circumferential surface of the recess 24 and the outer circumferential surface of the sliding portion 26 are as follows:
The clearance is small to maintain oil tightness, and the surface is finished with high precision to ensure smooth vertical sliding. Similarly, the inner peripheral surface of the guide hole 25 and the guide rod 2
The outer circumferential surface of No. 7 has a small clearance to maintain oil tightness, and has a highly accurate surface finish to allow good sliding in the vertical direction.

Further, when the ball valve body 20 is seated, the bottom surface of the valve body storage chamber 17 and the lower end of the sliding portion 26 of the member 21 are spaced apart from each other by a certain distance. Furthermore, the ball valve body 20
In the seated state, the guide rod 27 of the spring receiver member 21 is inserted into the guide hole 25.

Next, the operation of the pressure regulating valve for a fuel injection pump constructed in this way will be explained.

Fuel in the plunger chamber 4 is pressurized by driving the fuel injection pump 1, and the high-pressure fuel opens the first valve body 13 against the biasing force of the coil spring 15, and the valve body stopper 14 is opened.
The fuel is supplied to the fuel injection nozzle 12 through the through hole 14a of the valve housing 8, the communication hole IO of the valve housing 8, and the pipe 11. Then, fuel is injected from the fuel injection nozzle 12 into the internal combustion engine.

When the first valve body 13 is seated on the valve seat 16 at the end of this fuel pumping, a high-energy reflected wave (pressure horn wave) returns from the fuel injection nozzle 12 toward the pressure regulating valve 2 .

This high pressure wave causes the coil spring 22 to
The fuel flows through the through hole 18 of the stopper 19 and the valve body so that the ball valve body 20 opens against the biasing force of the ball valve and the pressure inside the pipe is set to a predetermined pressure (constant residual pressure) by the biasing force of the ball valve. It is returned to the plunger chamber 4 via the storage chamber 17 and the communication hole 23.

At this time, due to the high energy of the pressure wave, the spring receiver is
1 moves (lifts) downward to a predetermined amount of movement, the sliding part 26 enters the recess 24, and due to the damping effect of the fuel blocked in the recess 24, the sliding part 26 enters the recess 24. After that, the moving speed of the member 21 of the spring receiver suddenly decreases. As a result, the spring receiver suppresses overshoot of the member 21, thereby preventing more than a predetermined amount of fuel from returning from the recessed portion 9 to the plunger chamber 4.

On the other hand, when the ball valve body 20 opens to return fuel, the guide rod 27 fits into the guide hole 25 with a slight clearance, so the ball valve body 20 receives a lateral load due to the high energy of the pressure wave. Therefore, the coil spring 22 will not fall down and interfere with the wall surface of the valve body storage chamber 17.

In addition, when assembling the coil spring 22 into the valve body storage chamber 17, the coil spring 22 is placed vertically on the bottom surface of the valve body storage chamber 17 (the spring receiver is on the surface), and after the plug body 19 is press-fitted, the coil spring 22 is pressed. Coil spring 22 by welding or welding, etc.
The preload of the coil spring 22 can be adjusted depending on the press-fitting depth of the plug body 19, and the valve opening pressure of the ball valve body 20 can be adjusted. During this installation, the spring receiver can be installed while inserting the guide rod 27 of the member 21 into the guide hole 25, so the spring receiver can be attached to the member 21.
By moving the center of the valve body storage chamber 17 downward, the coil spring 22 can be vertically disposed. That is, since the surface of the spring receiver is at the bottom of the valve body storage chamber 17, it is impossible to confirm whether the coil spring 22 is installed vertically after the plug body 19 is press-fitted, but the coil spring 22 is always installed vertically. be able to. Therefore, if the plug body 19 is assembled with the coil spring 22 in a collapsed state, the ball valve body 20 will become unstable and the airtightness of the seal portion will deteriorate, making it impossible to adjust the valve opening pressure. , such a case does not occur in this embodiment.

Further, in this embodiment, the spring constant of the coil spring 22 is set to be large, and the spring receiver suppresses overshoot of the lift of the member 21. That is, the spring constant is 0. 58
By changing the weight from kg/mm to 1.5kg/mm, the spring receiver can increase the lift amount of the member 21 from 0.4mm to 0.2mm.
It has been confirmed that it can be made into mm.

As described above, according to this embodiment, the recess 24 is formed in the valve body storage chamber 17 in the first valve body 13, and the spring receiver is attached to the member 21 (second valve body). A sliding portion 26 (convex portion) that slides within the recessed portion 24 as the moving operation is performed is formed. Therefore, the ball valve body 20 (second valve body) opens against the biasing force of the coil spring 22 (second biasing means) due to the reflected wave from the fuel injection nozzle 12, and the fuel is injected. Although it is returned to the plunger chamber 4 (pressurizing chamber) of the pump l, the sliding part 26 slides inside the recess 24 and functions as a dashpot, and the spring receiver suppresses excessive movement of the member 21 and the coil spring 22 It is possible to prevent deterioration in responsiveness and improve performance.

In addition, a guide hole 25 (guide portion) is formed in the valve body storage chamber 17 of the first valve body 13, and a spring receiver is provided in the member 21 (second valve body) for movement of the member 21. A guide rod 27 (guide portion) that slides within the guide hole 25 was also formed. As a result, when assembling the coil spring 22, the guide rod 27 slides inside the guide hole 25, and the spring holder is attached to the member 2.
The coil spring 22 located on the outer periphery of the coil spring 22 is always vertical, so that uniform assembly can be ensured, and the coil spring 22 is prevented from collapsing even during subsequent operation. Therefore, deterioration of the adhesion of the seal portion of the ball valve body 20 and interference between the outer peripheral portion of the coil spring 22 and the wall surface of the valve body storage chamber 17 can be prevented, and reliability is improved.

This also means that by reducing the gap between the outer periphery of the coil spring 22 and the wall surface of the valve body housing chamber 17, the extra volume within the valve body housing chamber 17 can be reduced.

In addition, as an application example of this embodiment, a special oil for damping may be used. Further, in the above embodiment, the damping effect of the spring receiver appears after the member 2I has moved by a predetermined amount, but as shown in FIG. The sliding portion 26 may be located within the inner portion, so that the damping effect appears from the beginning of movement.

Further, as shown in FIG. 4, a recess 28 is formed in the valve body storage chamber I7 in the first valve body 13, and the spring receiver is attached to the member 2.
1, this spring receiver may form a sliding portion 29 that slides within the recess 28 as the member 21 moves, so that the damping effect and the guide function can be performed by one member.

Further, as shown in FIG.
0 is provided protrudingly, and the spring receiver is provided with its guide portion 3 on the member 21.
A sliding portion 31 may be formed to slide within 0. moreover,
As shown in FIG. 6, the spring receiver has a guide part 32 formed on the side surface of the member 21, and the guide part 32 slides on the wall surface of the valve body storage chamber 17 as the member 21 moves. Good too. Furthermore, as shown in FIG. 7, the spring receiver may be formed with a guide portion 33 on the side surface of the member 21 that slides on the wall surface of the valve body storage chamber 17 and covers the upper outer periphery of the coil spring 22.

Further, in this embodiment, the ball valve body 20 and the spring support member 21 are constructed as separate members, but they may be constructed as an integral structure.

[Second Embodiment] Next, a second embodiment corresponding to the third invention will be described. In this embodiment, the same components as in the first embodiment are designated by the same reference numerals, and detailed explanation thereof will be omitted.

As shown in FIG. 8, the valve body storage chamber 1 in the first valve body 13
A reduced diameter portion 34 serving as a fixed portion having approximately the same size as the outer diameter of the coil spring 22 is formed at the lower portion of the coil spring 7 . The lower end portion of the coil spring 22 is inserted into and supported by this reduced diameter portion 34 .

By doing so, the ball valve body 20 opens against the biasing force of the coil spring 22 due to the reflected wave from the fuel injection nozzle 12, and the fuel is returned to the plunger chamber 4 of the fuel injection pump. Since one end of the coil spring 22 is fixed, it is prevented from falling down. Similarly, when assembling the coil spring 22, one end of the coil spring 22 is fixed so that the coil spring 22 is always vertical, ensuring uniform assembly. Therefore, deterioration of the adhesion of the seal portion of the ball valve body 20 and interference between the outer peripheral portion of the coil spring 22 and the wall surface of the valve body storage chamber 17 can be prevented, and reliability is improved.

〔Effect of the invention〕

As described in detail above, according to the present invention, the excellent effect of improving the reliability due to the biasing means of the second valve body is exhibited.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a pressure regulating valve for a fuel injection pump according to the first embodiment, Fig. 2 is a sectional view of the main part of the pressure regulating valve, Fig. 3 is a sectional view of the main part of the pressure regulating valve, and Fig. 4 is a sectional view of the main part of the pressure regulating valve. 5 is a sectional view of the pressure regulating valve, FIG. 6 is a sectional view of the pressure regulating valve, FIG. 7 is a sectional view of the pressure regulating valve, and FIG. 8 is a sectional view of the pressure regulating valve.
FIG. 3 is a sectional view of a pressure regulating valve according to an embodiment. 1 is a fuel injection pump, 4 is a plunger chamber as a pressurizing chamber, 12 is a fuel injection nozzle, 13 is a first valve body, 15 is a coil spring as a first biasing means, 17 is a valve body storage chamber, 20 is a ball valve body constituting the second valve body, 21 is a spring bearing member constituting the second valve body, 22 is a coil spring as a second biasing means, 24 is a recessed portion, and 25 is a guide portion 26 is a sliding portion, 27 is a guide rod as a guide portion, and 34 is a reduced diameter portion as a fixed portion.

Claims (1)

[Scope of Claims] 1. Provided in a fuel passage between a pressurizing chamber of a fuel injection pump and a fuel injection nozzle, the pressurizing chamber of the fuel injection pump resists the urging force of the first urging means. a first valve body that supplies fuel to the fuel injection nozzle; and a second valve body provided in a valve body storage chamber in the first valve body, the fuel injection pump resisting the biasing force of the second biasing means. In the pressure regulating valve for a fuel injection pump, the pressure regulating valve is provided with a second valve body that returns fuel to a pressurizing chamber, and the valve body storage chamber and the second valve body form an uneven part, and the convex part is A pressure regulating valve for a fuel injection pump, characterized in that the second valve body is configured to slide within a recessed portion as the second valve body moves. 2. A channel provided in the fuel passage between the pressurizing chamber of the fuel injection pump and the fuel injection nozzle and supplying fuel from the pressurizing chamber of the fuel injection pump to the fuel injection nozzle against the urging force of the urging means. a second valve body that is provided in a valve body storage chamber in the first valve body and returns fuel from the fuel injection nozzle to the pressurizing chamber of the fuel injection pump against the biasing force of the coil spring. In the pressure regulating valve for a fuel injection pump, the valve body storage chamber or the second valve body is provided with a guide portion for moving the second valve body only in a predetermined direction. Pressure regulating valve for fuel injection pump. 3. A channel provided in the fuel passage between the pressurizing chamber of the fuel injection pump and the fuel injection nozzle and supplying fuel from the pressurizing chamber of the fuel injection pump to the fuel injection nozzle against the urging force of the urging means. a second valve body that is provided in a valve body storage chamber in the first valve body and returns fuel from the fuel injection nozzle to the pressurizing chamber of the fuel injection pump against the biasing force of the coil spring. 1. A pressure regulating valve for a fuel injection pump comprising: a fixing portion for fixing an end of the coil spring to the valve body storage chamber.