JPH11107886A - Pulsation damping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost pulsation damping device to simplify structure by a method wherein a through-part is eliminated from a diaphragm, and a material not penetrating fuel is selected serving as a diaphragm. SOLUTION: In a pulsation damping device formed such that by exerting a pressure of fluid on a diaphragm 43, pulsation of a fluid pressure is damped, a disc member 45 is arranged between a spring 46 and a diaphragm 43. The diaphragm 43 is combination structure of a sheet made of rubber and a sheet made of synthetic resin. A support part 42A with which the diaphragm 43 pressed by the spring 46 makes contact is provided. The spring 46 is pressed in the contraction part 41A and the disc member 45 of an upper casing 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a device for attenuating a pulsation of fluid pressure in a piping system, and more particularly, to a device for attenuating a pulsation of fuel injected in piping of a fuel injection system of an internal combustion engine. Pulsation damping device effective for

[0002]

2. Description of the Related Art Conventionally, a piping system is provided with a pulsation damping device for attenuating pulsation of a fluid flowing in the piping and suppressing fluctuations in fluid pressure in the piping within a predetermined width. In particular, in the fuel injection system of an internal combustion engine, if the pressure of the fuel (gasoline) injected into the intake air or the cylinder pulsates, the ratio of air to fuel fluctuates, and the output decreases and the fuel efficiency deteriorates. Cause.

Hereinafter, an example of a conventionally known pulsation damping device will be described with reference to FIG. The fuel in the fuel tank 1 is supplied by a fuel pump 2, passes through a fuel filter 3, reaches a pulsation damping device 4, and is sent from the pulsation damping device 4 to a delivery pipe 5. The delivery pipe 5 is provided with a fuel injection valve 6, and the fuel is injected into the intake pipe or the cylinder by the fuel injection valve 6. A pressure adjusting device 7 is connected to the delivery pipe 5 so as to return the fuel into the fuel tank 1 when the fuel pressure in the delivery pipe 5 becomes higher than a set value.

The pulsation damping device 4 shown in FIG. 11 is constructed as follows. With reference to FIG. 12, the upper casing 11 and the lower casing 12 caulk the peripheral edges of two diaphragms 13 made of rubber containing a base cloth. A valve plate 14 is disposed on one side of the diaphragm 13, and a plate member 15 is disposed on the other side of the diaphragm 13, and a projection 14 </ b> A of the valve plate 14 passes through the diaphragm 13 and is fixed to the plate member 15. Thereby, the diaphragm 13 is fixed to the valve plate 14 and the plate member 15.

The valve plate 14 has a skirt portion 14B
Is provided. A spring 16 for pressing the skirt portion 14B against the receiving portion 12A is provided on the plate member 15. The spring 16 is urged in a direction to press the skirt portion 14B against a receiving portion 12A formed in the lower casing 12, and when no fluid pressure acts on the lower casing 12, the skirt portion 14B is pressed by the spring 16's pressing force. 14B is in contact with the receiving portion 12A.

The upper casing 11 has a breathing opening 11A.
And an on-off valve 17 for opening and closing the breathing port 11A. Further, a cap 18 is placed on the upper casing 11 to prevent water and dust from entering from the breathing port 11A.

The operation of the conventionally known pulsation damping device configured as described above will be described. The pressure of the fuel is acting on the fluid pressure action space 19 inside the lower casing 12, and if pulsation occurs in the fuel pressure now, the pressure in the fluid pressure action space 19 also pulsates. In order to cancel the pulsation, the diaphragm 13 moves up and down against the spring 16, and the pulsation is attenuated.

[0008]

However, the known pulsation damping device has the following problems. That is, in the conventionally known pulsation prevention device, the diaphragm 1
3, a valve plate 14 is provided, and a diaphragm 13 is formed by the valve plate 14 and the plate member 15.
Are sandwiched between the two. For this reason, fuel flows through the upper casing 1 through the penetrating portion of the diaphragm 13.
There is a possibility of leaking into 1. Also, the valve plate 14
Therefore, the cost is high and the size is inevitably increased.

Next, since the diaphragm 13 is made of a rubber material, fuel permeates through the diaphragm 13 and accumulates as fuel gas in the upper casing 11.
The conventionally known pulsation damping device is provided with the breathing port 11A and the opening / closing valve 17 for removing the permeated fuel gas, so that the structure becomes complicated and the cost becomes high. Further, since the breathing port 11A and the opening / closing valve 17 are provided, a structure for preventing intrusion of water and dust is required. For this reason, the cap 18 is conventionally covered on the upper casing 11, but the structure is complicated and high. Costs are inevitable. In addition, when the fluid is fuel, the rubber diaphragm swells or is degraded in quality by the fuel, so it needs to be replaced early, and there is a problem in durability and reliability. .

Accordingly, an object of the present invention is to improve the drawbacks of the above-mentioned known pulsation damping device, to eliminate the penetration portion from the diaphragm, and to select a material that does not allow fuel to permeate as the diaphragm, thereby simplifying the structure. An object of the present invention is to provide a pulsation damping device which has a low cost.

[0011]

The feature of the present invention lies in the following constitution. That is, a diaphragm, a spring pressing the diaphragm to one side, and a fluid pressure applied to the other side of the diaphragm, the fluid pressure acting on the diaphragm to attenuate the pulsation of the fluid pressure. Pulsation damping device
A dish member is provided between the spring and the diaphragm so that there is no portion penetrating through the diaphragm.

Another feature of the present invention resides in that the diaphragm has a combined structure of a rubber diaphragm and a diaphragm made of a synthetic resin sheet. Is provided on the side on which.

Another feature of the present invention resides in that the spring is pressed into and held in the reduced diameter portion of the upper casing, and further that the spring is pressed and held in the dish member.

Another feature of the present invention is that the diaphragm is provided with an engaging portion fixed to the dish member.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the present invention. The pulsation damping device is composed of an upper casing 21 and a lower casing 22, and the peripheral edge of the diaphragm 23 is caulked by the upper casing 21 and the lower casing 22. In this embodiment, the diaphragm 23 has a two-diaphragm structure made of rubber containing a base cloth. However, as described later, this embodiment of the present invention is not limited to the structure and material constituting the diaphragm 23. Absent.

A receiving portion 22 is provided on one side of the diaphragm 23.
A is disposed, and the receiving portion 22A is formed integrally with the lower casing 22 in this embodiment. A dish member 25 is disposed on the other side of the diaphragm 23, and the diaphragm 23 is in frictional contact with the dish member 25. Plate member 2
5 is provided with a spring 26, which presses the diaphragm 23 against a receiving portion 22 </ b> A formed on the lower casing 22. When no fluid pressure is acting in the lower casing 22, the spring 26
The diaphragm 23 is in contact with the receiving portion 22A due to the pressing force of the above.

The upper casing 21 has a breathing opening 21A.
And an on-off valve 27 for opening and closing the breathing port 21A. Here, since no fluid leaks into the upper casing 21, the on-off valve 27 can be omitted. The reason is that the diaphragm 23 has no penetrating portion, so that there is no possibility that fluid leaks through the penetrating portion. In order to prevent water and dust from entering through the breathing opening 21A, the cap 28 is provided with the upper casing 21.
Is covered.

The operation of the pulsation damping device according to one embodiment of the present invention configured as described above will be described as follows. The pressure of the fuel is acting on the fluid pressure action space 29 inside the lower casing 21, and if the fuel pressure pulsates now, the pressure in the fluid pressure action space 29 also pulsates. In order to cancel the pulsation, the diaphragm 23 moves up and down against the spring 26, and the pulsation is attenuated.

Since the pulsation damping device according to one embodiment of the present invention is configured as described above, the diaphragm 23 has no penetrating portion as in the conventional structure. Therefore, the fuel acting on the fluid pressure working space 29 does not leak into the upper casing 21 through the penetrating portion,
The reliability of the pulsation damping device is improved. Further, the on-off valve 27 for trapping the leaked fuel can be omitted, so that the structure can be simplified and the cost of the device can be reduced.

Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view showing another embodiment of the present invention. In the embodiment of FIG. 1, a conventionally known two-layer rubber diaphragm made of a base cloth containing a base fabric is used as the diaphragm. However, in the rubber diaphragm, fuel permeates and fuel gas accumulates in the upper casing. ,
In this embodiment, the diaphragm is made of a material that does not penetrate the fuel.

Referring to FIG. 2, a peripheral edge of a diaphragm 33 is caulked by an upper casing 31 and a lower casing 32 which constitute a pulsation damping device. In this embodiment, the diaphragm 33 has a combination structure of a rubber diaphragm 33A made of rubber containing a base cloth and a synthetic resin diaphragm 33B made of a synthetic resin sheet. Here, the rubber diaphragm 33A is arranged on the upper casing 31 side, and the synthetic resin diaphragm 33 is disposed.
Although it is desirable to dispose B on the lower casing 32 side, the reverse arrangement structure, that is, a structure in which the synthetic resin diaphragm 33B is disposed on the upper casing 31 side and the rubber diaphragm 33A is disposed on the lower casing 32 side may be adopted. good. In addition, when a synthetic resin is referred to here, a synthetic resin sheet product referred to by a trade name such as Teflon, nylon, or vinyl is preferable, but there is no permeation of a fuel such as vinyl chloride or polyethylene, and the fuel is hardly deteriorated by the fuel. Other synthetic resins may be used.

A receiving portion 32A formed on the lower casing 32 is disposed on one side of the diaphragm 33, and a dish member 35 is disposed on the other side of the diaphragm 33. The diaphragm 33 is in frictional contact with the plate member 35, and the plate member 35 is provided with a spring 36 that presses the diaphragm 33 against a receiving portion 32 </ b> A formed on the lower casing 32. The spring 36 is urged in a direction to press the diaphragm 33 against the receiving portion 32A. When no fluid pressure is applied to the inside of the lower casing 32, the diaphragm 36 is pressed by the pressing force of the spring 36.
3 is in contact with the receiving portion 32A.

The upper casing 31 is not provided with a breathing port or an on-off valve as seen in a conventional pulsation damping device, and is completely closed. Therefore, no cap for preventing intrusion of water or dust is provided.

The pulsation damping device according to another embodiment of the present invention configured as described above is advantageous in the following points as compared with the embodiment having the structure shown in FIG. In the embodiment shown in FIG. 1, since the diaphragm 23 is made of rubber, the fuel permeates and the fuel gas accumulates in the upper casing 21 because the diaphragm 23 is made of rubber, and a breathing port 21A for releasing the accumulated fuel gas is provided. It is necessary to provide a cap 28 on the upper casing 21 to prevent intrusion of dust and dust.
In the embodiment shown in FIG. 2, since the diaphragm 33 has a combination structure of the synthetic resin diaphragm 33B and the rubber diaphragm 33A, the synthetic resin diaphragm 33B prevents fuel from penetrating, and the upper casing 31
Since the fuel gas does not accumulate inside, the breathing port and the cap can be omitted.

Next, another embodiment of the present invention will be described. FIG. 3 is a sectional view showing a preferred embodiment of the present invention. In the embodiment shown in FIG. 2, there is a possibility that the spring 36 is displaced in the left-right direction of the drawing due to vibration, or the dish member 35 is displaced in the left-right direction of the drawing. 33
Since foreign matter easily enters between B and the receiving portion 32A, the synthetic resin diaphragm 33B may be damaged when the foreign matter is caught. The embodiment shown in FIG. 3 is an embodiment having a structure for improving the above-mentioned disadvantage.

Referring to FIG. 3, upper casing 41
Is formed with a reduced diameter portion 41A having a reduced diameter. FIG.
As shown in FIG. 4 which is an AA cross-sectional view of FIG.
Are formed with a plurality of protrusions 44 in the circumferential direction. The spring 46 includes a plurality of protrusions 44 of the reduced diameter portion 41A.
Partially pressed into the inside. Also, on the inner periphery of the plate member 45,
As shown in FIG. 5, which is a sectional view taken along the line BB in FIG. 3, a plurality of protrusions 45A are formed in the circumferential direction. The spring 46 is partially pressed into the plurality of protrusions 45A. Further, a plurality of radial grooves 42A1 are formed in the receiving portion 42A formed in the lower casing 42, as shown in FIG. 6, which is a cross-sectional view taken along the line CC in FIG. The cross-sectional shape of the groove 42A1 is shown in FIG.
As shown in (B) and (C), a groove having a rectangular cross section may be used, a groove having a trapezoidal cross section, or a groove having an arcuate cross section may be used. Note that a structure in which a plurality of radial ridges 42A2 are formed instead of the plurality of radial grooves 42A1 may be employed. In this case, the cross-sectional shape of the protrusion 42A2 is as shown in FIGS.
As shown in (F), a ridge having a square cross section, a trapezoidal cross section, or a ridge having an arc cross section may be used. Next, in the embodiment of FIG. 3, a filter 50 for removing foreign substances in the fluid is provided inside the lower casing 42, which is a path through which the fluid pressure acts on the diaphragm 43. The filter 50 includes a reduced diameter portion 42B
Is formed on the reduced diameter portion 42B, the mounting is easy, and the falling off after the mounting is reduced. Structures other than those described above are the same as those in the embodiment shown in FIG. 1 or FIG. 2, and the description thereof will be omitted.

The pulsation damping device constructed as described above according to the preferred embodiment of the present invention is advantageous in the following points as compared with the embodiment having the structure shown in FIG. In this embodiment, since the spring 46 is press-fitted into the reduced diameter portion 41A, and furthermore, the spring 46 is press-fitted into the plate member 45, the position of the spring 46 does not shift even when subjected to vibration. The position of 45 does not shift. Furthermore, even if foreign matter enters between the diaphragm 43 and the receiving portion 42A, the foreign matter falls into the groove 42A1, so that the foreign matter does not bite between the diaphragm 43 and the receiving portion 42A. Is prevented from being damaged. Further, according to the structure in which the filter 50 is provided, foreign matter is prevented from entering the diaphragm side, so that damage to the diaphragm due to foreign matter is further prevented.

In the embodiment shown in FIG. 3, the spring 46 is connected to the reduced diameter portion 41A of the upper casing 41 or the plate member 45.
However, the present invention is not limited to the above-described embodiment, and the spring 46 may be connected to the upper casing 41.
This also includes a structure in which the entire circumference is pressed into the reduced diameter portion 41A or the dish member 45. That is, as shown in FIGS. 8A and 8B, the spring 46 is connected to the upper casing 41.
(The entire circumference press-fitting) may be performed while the entire diameter of the reduced diameter portion 41A or the dish member 45 is kept in contact with the entire circumference.

According to the embodiment shown in FIG. 3, the movement of the plate member is restricted by the spring, but the restriction by the spring is not sufficient. Therefore, in the embodiment shown in FIG. 9, the movement of the plate member is restricted by the upper casing. That is, an engaging portion 53C projecting upward is provided on the diaphragm 53, and the engaging portion 53C penetrates and is fixed to the plate member 55.

The fixing structure between the engaging portion 53C and the plate member 55 is not limited to the illustrated embodiment, and the plate member 55 is connected to the diaphragm 53 in order to prevent the plate member 55 from shifting in the left-right direction. And various known fixing structures. With this structure, the plate member 55
The movement in the left-right direction in the figure is prevented, and the noise and vibration are reduced, and the pulsation damping effect is also improved.

One of the main points of the present invention is to use a synthetic resin having high fuel resistance as the diaphragm. Therefore, the present invention includes the embodiment shown in FIG. That is, the conventionally known diaphragm 63 is connected to the valve plate 64.
In the pulsation damping device penetrated by the projection 64A of the above, and the projection 64A is fixed to the plate member 65, the diaphragm 63 has a combination structure of a rubber diaphragm 63A made of rubber and a synthetic resin diaphragm 63B. It is. In this structure, since the fuel gas does not accumulate due to the permeation of the fuel, the upper casing 61 does not need a breathing port or an on-off valve. In the figure,
Reference numeral 66 denotes a spring.

[0032]

According to the present invention constructed and operated as described above, the following effects can be obtained.

First, in a structure using a diaphragm having no penetrating portion, no fluid leaks into the upper casing through the penetrating portion, so that an on-off valve is unnecessary and the structure is reduced. Since simplification is achieved, cost reduction can be obtained.

In the case where the diaphragm has a combination structure of a rubber sheet and a synthetic resin sheet, there is no fluid, particularly fuel, penetrating into the upper casing through the diaphragm. In addition to the structure that can be omitted, the cap that prevents intrusion of water and dust can be omitted, simplifying the structure,
Cost reduction and weight reduction can be obtained.

In the case of using a two-layer diaphragm composed of a rubber diaphragm and a synthetic resin diaphragm, if the synthetic resin diaphragm is provided on the side where the fluid pressure acts, the rubber diaphragm will not be deteriorated by fuel. This eliminates the need for early replacement and improves durability and reliability.

According to the structure in which the receiving portion is provided with irregularities, such as a plurality of radially formed grooves or a plurality of radially formed ridges, in which the diaphragm partially abuts, foreign matter is received by the diaphragm. This prevents the diaphragm from being jammed, thereby preventing the diaphragm from being damaged.

In the structure in which the spring is press-fitted into the upper casing and the plate member, the displacement of the plate member and the spring is prevented, the core is prevented from being displaced at the time of assembling, and the assembling work is facilitated. There are no defects.

According to the structure in which the filter for removing the foreign matter in the fluid is provided in the path where the fluid pressure acts on the diaphragm,
Since there is no foreign matter caught between the diaphragm and the receiving portion, the breakage of the diaphragm can be prevented without providing the receiving portion with a groove or a ridge.

When the diaphragm is fixed to the plate member, the plate member is prevented from moving in the left-right direction, the displacement of the diaphragm becomes linear, and the pulsation damping characteristic becomes constant.

According to the structure using a combination diaphragm of a synthetic resin diaphragm and a rubber diaphragm in a conventionally known pulsation damping device having a valve plate, accumulation of fuel gas due to permeation of fuel is prevented, and furthermore, synthetic resin is prevented. According to the structure in which the diaphragm made of rubber is provided on the side on which the fluid pressure acts, deterioration of the rubber diaphragm made by the fuel is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a pulsation damping device according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a pulsation damping device according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a pulsation damping device according to a preferred embodiment of the present invention.

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 is a sectional view taken along the line BB of FIG. 3;

FIG. 6 is a view taken in the direction of arrows CC in FIG. 3;

FIG. 7 is a sectional view taken along line DD of FIG. 6;

FIGS. 8A and 8B are cross-sectional views showing another embodiment of the spring press-fitting structure.

FIG. 9 is a sectional view showing a pulsation damping device according to still another embodiment of the present invention.

FIG. 10 is a sectional view showing a pulsation damping device according to still another embodiment of the present invention.

FIG. 11 is a diagram showing a fuel injection system to which the pulsation damping device of the present invention is applied.

FIG. 12 is a sectional view showing an example of a conventionally known pulsation damping device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Upper casing 21A Breathing opening 22 Lower casing 22A Receiving part 23 Diaphragm 25 Dish member 26 Spring 27 On-off valve 28 Cap 29 Fluid pressure working space 31 Upper casing 32 Lower casing 32A Receiving part 33 Diaphragm 33A Rubber diaphragm 33B Synthetic resin diaphragm Dish member 36 Spring 41 Upper casing 41A Reduced diameter portion 42 Lower casing 42A Receiving portion 42A1 Groove portion 42A2 Ridge 42B Reduced diameter portion 43 Diaphragm 44 Projection 45 Dish member 45A Projection 46 Spring 50 Filter 51 Upper casing 53 Diaphragm 53 C 55 Dish member 61 Upper casing 63 Diaphragm 63A Rubber diaphragm 63B Synthetic resin diaphragm 4 the valve plate 64A projecting portion 65 dish member 66 spring

Claims (20)

[Claims] A diaphragm comprising: a diaphragm; a spring for pressing the diaphragm to one side; and a fluid pressure applied to the other side of the diaphragm, wherein the pressure of the fluid acts on the diaphragm to attenuate the pulsation of the fluid pressure. A pulsation damping device, wherein a dish member is provided between the spring and the diaphragm. 2. The apparatus according to claim 1, wherein the peripheral edge of the diaphragm is sandwiched between an upper casing and a lower casing, and the spring and the dish member are provided between the top of the upper casing and the diaphragm. Pulsation damping device. 3. The pulsation damping device according to claim 1, wherein the diaphragm has a combination structure of a rubber diaphragm and a diaphragm made of a synthetic resin sheet. 4. The pulsation damping device according to claim 3, wherein a diaphragm made of a synthetic resin sheet is provided on a side on which the fluid pressure acts. 5. The pulsation damping device according to claim 1, further comprising a receiving portion with which a diaphragm pressed by a spring abuts. 6. The pulsation damping device according to claim 5, wherein the receiving portion is formed integrally with the lower casing. 7. The pulsation damping device according to claim 5, wherein the receiving portion is provided with projections and depressions with which the diaphragm partially contacts. 8. The pulsation damping device according to claim 7, wherein the unevenness provided on the receiving portion is a plurality of radially formed grooves. 9. The pulsation damping device according to claim 7, wherein the unevenness provided on the receiving portion is a plurality of ridges formed radially. 10. The pulsation damping device according to claim 2, wherein a reduced diameter portion is provided in the upper casing, and a spring is press-fitted into the reduced diameter portion. 11. A projection is formed on the inner peripheral surface of the reduced diameter portion, and a spring is press-fitted into the projection.
The pulsation damping device according to 0. 12. The pulsation damping device according to claim 1, wherein a spring is pressed into an inner peripheral surface of the dish member. 13. A projection formed on the inner peripheral surface of the dish member, and a spring is press-fitted into the projection.
3. The pulsation damping device according to 2. 14. The pulsation damping device according to claim 1, wherein a filter for removing foreign matter in the fluid is provided in a path where the fluid pressure acts on the diaphragm. 15. The pulsation damping device according to claim 2, wherein a reduced diameter portion is formed in the lower casing, and a filter is provided in the reduced diameter portion. 16. The pulsation damping device according to claim 1, wherein the diaphragm has an engaging portion fixed to the plate member. 17. The pulsation damping device according to claim 1, wherein the pulsation damping device is a device provided in a fuel injection device of an internal combustion engine. 18. A diaphragm comprising a diaphragm, a spring for pressing the diaphragm to one side, and a fluid pressure applied to the other side of the diaphragm. The diaphragm penetrates the center of the diaphragm and is formed by a plate member and a valve plate. In a pulsation damping device, the diaphragm is clamped so that a peripheral edge of the diaphragm is clamped by an upper casing and a lower casing, and the pulsation of fluid pressure is attenuated by applying a fluid pressure to the diaphragm. A pulsation damping device having a combined structure of a sheet made of a synthetic resin and a sheet made of a synthetic resin. 19. The pulsation damping device according to claim 18, wherein a sheet made of synthetic resin is provided on a side on which fluid pressure acts. 20. The pulsation damping device is a device provided in a fuel injection device of an internal combustion engine.
Alternatively, the pulsation damping device according to claim 19.