JPS63106493A - Pulsation preventive structure of pump - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pulsation prevention structure for a pump such as an automobile fuel supply pump.

[Prior Art and Problems to be Solved by the Invention] In general, there are various types of pumps of this type, such as vane type, trochoid type, and turbine type. In the pump operation, pulsation inevitably occurs, and this causes the hoses and piping connected to the pump's fluid flow path, as well as the parts that are attached to these, to vibrate, and this causes resonance, which is a major cause of noise generation. This is not a lie, but also on the supply side that receives fluid supply by pump operation.

The disadvantage is that the fluid is supplied in a pulsating manner, which has negative effects. Conventionally, therefore, a dedicated pulsation absorbing device such as a damper was separately provided in the pump itself or in the fluid flow path to absorb the pulsation. However, this pulsation absorbing device has drawbacks such as a complicated structure, a large shape, and an expensive cost. The advent of a means was highly desired.

[Means for solving the problem of interstitial layer] In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a pulsation prevention structure for a pump that can eliminate these drawbacks. The fluid flow path is provided with a hose body that elastically deforms in response to the pulsation of the pump.

According to the present invention, with this configuration, pulsation can be reliably absorbed by the hose body provided in the fluid flow path of the pump, without using a pulsation absorbing device that was conventionally required.

[Example 1] Next, in drawing 0, which describes an example of the present invention based on the drawings, 1 is a fuel supply pump installed in a fuel tank 2 of an automobile, and the pump 1 is, for example, a trochoid pump. It is constructed using a positive displacement pump of
A filter 4 is connected to the inlet port 3 of the pump 1, so that fuel in the tank 2 flows into the pump 1 in a filtered state by pump operation. Further, one end portion of a hose body 6 in which the present invention is implemented is integrally connected to the discharge port 5 of the pump 1, as will be described later.
The other end of the hose body 6 is integrally connected to the end of a metal pipe 8 attached to the wall surface of the fuel tank 2 by a mounting plate 7. The fuel discharged in a pulsating manner from the discharge port 5 by the operation of the pump 1 is then discharged from the hose body 6. It is supplied to an injector (not shown) through a pipe 8.

The hose body 6 is made of a flexible rubbery elastic material, and may be molded using an oil-resistant resin material such as acrylonitrile-butadiene rubber (NBR) or fluororesin. , its cross-sectional shape is a substantially rectangular square shape, and as will be described later, in response to pulsations generated by the operation of the pump 1, the cross-sectional shape changes in cross-sectional area from the natural cross-sectional shape. It is set to undergo elastic deformation.

Then, the embodiments of the present invention will be discussed more specifically by comparing them with the conventional ones. Here, as for the hose body, as mentioned above, the one with the rectangular cross section shown in FIG. (second hose body).

For a conventional hose body with a circular cross section and a hose body using metal piping, the pulsation state at the inlet and outlet was measured based on the pressure difference, and the results were reported. As shown in Table 1, where pump 1
The discharge pressure was 2.05 kg/c+s'' in each case, and the pulsation state was measured using a synchroscope at the inlet and outlet of the hose body.Here, the total length of the hose body 6 was 12, and the Approximately 20 portions were inserted into the discharge port 5 and piping 8, and the thread layer 9 in the second hose body was
teeth.

When converting the hose body 6 into a circular cross-section, the hose body has an inner diameter of 7.5 m and an outer diameter of 13.5 m, and has 12 right-handed and left-handed threads braided together. , and the fiber knitting angle θ is set to 55 degrees.

Table 1 Judging from these results, 1. The hose body of the present invention that elastically deforms in response to pulsation (first hose body, second hose body) is extremely high in both cases compared to other hose bodies. It can be seen that it has a pulsation reduction rate. In the case of the first hose body, the reduction rate is almost comparable to that of current large pulsation absorbers.

Furthermore, the reduction rate of the second hose body is approximately comparable to that of a small pulsation absorber, and based on this fact.

It becomes clear how effective the hose body implementing the present invention is in terms of preventing pulsation. As a result 1, in the present invention,
Even if a pulsation absorption device is not used, it is possible to achieve substantially the same reduction in pulsation as using a pulsation absorption device. This is because the hose body 6 of the embodiment described above undergoes elastic deformation so that its rectangular cross section becomes circular in response to the pulsation from the pump 1, and the cross-sectional area thereof increases and decreases. This can be inferred, and this is also supported by the fact that the reduction rate is low for conventional hose bodies, which have a circular cross section from the beginning and can hardly be expected to undergo elastic deformation due to pulsation. The one with the thread waste 9 has excellent pressure resistance, and therefore has extremely high practicality.

As can be seen from this example, the hose body 6 required for the flow path of the pump 1 is configured to be elastically deformed in response to the pressure difference caused by the pulsation of the pump 1, which is an extremely simple construction. Despite the structure, it is possible to absorb the pulsation generated by pump operation extremely effectively, so even if it is simple and does not have the pulsation absorbing device that was required in the past, it can create a pulsation-free pump flow path. Therefore, it can greatly contribute to reducing the size and weight of the pump flow path, and it is also possible to significantly reduce costs.

In the embodiment, the pump 1 is an in-tank type built inside the fuel tank 2, and the hose body 6 is located between the discharge port 5 of the pump 1 and the external connection pipe 8 in the fuel tank 2. Therefore, the pulsation caused by pump operation is immediately absorbed by the hose body 6 within the fuel tank 2 without going outside at all, and the piping 8 is kept in a rectified state without pulsation. Fuel will flow. Therefore, the adverse effects of pulsation are prevented at an early stage, and even if the hose body 6 is elastically deformed due to pulsation, the effect is carried out within the fuel tank 2, so there is no adverse effect [Implementation] Example 2.3] In Example 1, it was found that the yarn layer 9 braided into the hose body also provided considerable pulsation prevention.In order to further obtain this high pulsation prevention effect, the fiber braiding angle O
We investigated how the pulsation reduction rate changes by changing various values. As for the hose body 6 used in this example, a hose body 6 with a circular cross section and a hose body 6 which was flattened into an elliptical shape were examined. At this time, the hose body 6 used had an inner diameter of 5 mm, an outer diameter of 13.5 mm, and was braided with 12 right-handed and left-handed threads, and the hose body was measured. The conditions were the same as in Example 1. The results are shown in Table 2.

FIG. 5 shows the results of pulsation measurement at the input section and the outlet section for the circular type.

Table 2 From these results, it is clear that the pulsation reduction rate is approximately 5% higher for those with an elliptical cross section that is not circular, regardless of the knitting angle, which suggests how effective the present invention is. However, what is even more surprising is that it is observed that the smaller the knitting angle of the yarn layer 9, the greater the pulsation reduction rate. Therefore, 1g for a hose body with a circular cross section! Figure 6 shows a graph showing how the rupture pressure and reduction rate change depending on changes in the angle θ. In order to assume that the knitting angle θ is approximately 5
It only needs to be 0 degrees or less, and by doing this, even if the hose body has a circular cross section, the hose body can have an effective pulsation prevention effect within the allowable range within the required bursting pressure. You will have a choice. If an even higher pulsation prevention effect is required, a non-circular cross section such as an ellipse may be selected. Here, for hoses with an elliptical cross section, the bursting pressure is substantially the same as for hoses with a circular cross section, and when both ends of the hose body are inserted into the discharge port 5 or piping 8, the ends of the hose open in a substantially circular shape. Therefore, the tightening effect of the stop band is different from that of a case with a part of a square corner.
Like the circular shape, it is convenient because it is almost uniform.

[Examples 4 to 6] Furthermore, as for the cross-sectional shape of the hose body that elastically deforms in response to pulsation, there are various types of hose bodies, such as one having a triangular cross-section as shown in Example 4 shown in FIG. 7, and one having a diamond-shaped cross-section. It was observed that these non-circular shapes had substantially the same pulsation absorbing effect as in the case of the above-mentioned Example. In the case of such a rectangular shape, one side may be made softer than a corner part to provide elasticity so that it can be more elastically deformed by receiving pulsation.
Furthermore, as in Embodiment 5 shown in FIG. 8, uneven portions may be formed on the hose body 6 so that the uneven portions are elastically deformed in response to pulsations, and in this case as well, there is a pulsation absorbing effect. was observed.

Furthermore, as a means for elastically deforming in response to pulsation, a general-purpose hose with a circular cross section is used without making the hose body itself such a cross-sectional shape, and this is transformed into an elastic material as shown in Example 6 shown in FIG. The hose body 6 may be configured to be clamped by the plates 10 or compressed by the bullets 11 so that the hose body 6 is elastically deformed by the pulsation, and it has been observed that this also has the effect of absorbing pulsation. .

[Operations and Effects] In summary, since the present invention is configured as described above, the pulsation generated by pump operation causes the hose body, which must be provided in the fluid flow path of the pump, to be elastically deformed due to the pulsation. Even with a simple pump flow path structure that omits the conventionally required pulsation absorbing device, pulsation can be prevented even if the structure is extremely simple. This not only significantly reduces noise generation due to pulsation, but also greatly contributes to reducing the size and weight of the pump itself. Negative effects can also be reduced, and significant cost reductions can also be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the pulsation prevention structure for a pump according to the present invention, and FIG. 1 is a structural diagram showing the installation of a fuel pump, and FIGS. 3A and 3B are sectional views of hose bodies of 2nd and 3rd embodiments in which the present invention is implemented, and FIG. 4 is an explanatory diagram showing the weaving angle θ, Fig. 5 is a graph showing the relationship between pulsation reduction rate and burst pressure when the weaving angle is changed in the second embodiment, and Fig. 6 is a graph showing the relationship between the pulsation reduction rate and the burst pressure when the knitting angle of the hose body in the second embodiment is changed. Pulsation measurement result diagram,
7A and 7B are sectional views of the hose body of the fourth embodiment, FIG. 8 is a perspective view of the hose body of the fifth embodiment, and FIG. 9A,
B is a perspective view and a sectional view of main parts of a hose body of a sixth embodiment. In the figure, 1 is a pump, 2 is a tank, and 6 is a hose body. Patent Applicant: Mitsuba Electric Manufacturing Co., Ltd. Figure 5 Prisoner's - 忰空沫 (○ Procedural Correction Band (,,!,

Claims (1)

[Scope of Claims] 1) A pulsation prevention structure for a pump, characterized in that a hose body that elastically deforms in response to pulsations of the pump is provided in a fluid flow path of the pump. 2) The elastically deformable hose body has a substantially circular cross-sectional shape, and a yarn layer braided in a round braid shape in the middle is braided with a fiber braid angle set to be smaller than 50 degrees. A pulsation prevention structure for a pump according to claim 1, characterized in that: 3) The pulsation prevention structure for a pump according to claim 3, wherein the elastically deformable hose body has a non-circular cross-sectional shape. 4) Claim 1, wherein the elastically deformable hose body has a rectangular or elliptical shape.
Anti-pulsation structure of the pump described in Section 1. 5) The pulsation prevention structure for a pump according to claim 4, wherein the elastically deformable hose body has a circular braided yarn layer woven in the middle thereof. 6) The elastically deformable hose body has a two-layered hose structure, an inner and outer hose, and a connecting member is interposed between both hoses so that a space is formed between them, and the part of the inner hose corresponding to the space is pulsating. 2. The pulsation prevention structure for a pump according to claim 1, wherein the structure is configured to elastically deform in response to the pulsation. 7) Pump pulsation prevention according to claim 1, wherein the pump is a fuel supply pump housed in a fuel tank, and the hose body is housed in the fuel tank. structure.