JP2021173327A - Pulsation attenuation device - Google Patents

Abstract

To provide a pulsation attenuation device capable of increasing a surplus elastic energy capacity of an elastic body capable of being used in pulsation absorption.SOLUTION: A pulsation attenuation device 1 of a fluid pressure circuit comprises: an internal flow path 2 forming a part of the fluid pressure circuit; a fluid pressure chamber 3 provided at a position facing the internal flow path 2; and an elastic body 4 provided so as to separate the internal flow path 2 and the fluid pressure chamber 3, where the fluid pressure chamber 3 is provided so that pressurized fluid can be circulated between itself and the fluid pressure circuit; the elastic body 4 can receive fluid pressure from each of the internal flow path 2 and the fluid pressure chamber 3; and an area difference is provided between a flow path side pressure receiving area S1 and a flow path side pressure receiving area S2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pulsation damping device.

There is a fluid power system that uses working fluid to drive mechanical devices. In such a system, in order to increase the energy density, a pump such as a positive displacement pump is used to increase the fluid pressure of the working fluid. On the other hand, the positive displacement pump has a drawback that the working fluid causes pressure pulsation and the fluid pressure fluctuates from the reference pressure. Therefore, a pulsation damping device for absorbing the pulsation and holding the fluid pressure of the working fluid at a reference pressure is indispensable for the fluid power system.

Conventionally, as a pulsation damping device, there is a device that utilizes elastic deformation of an elastic body (see, for example, Patent Document 1 and Non-Patent Documents 1 and 2). The conventional pulsation damping device has an atmospheric pressure opening portion, and an elastic body is arranged so as to separate the flow path of the working fluid from the atmospheric pressure opening portion. The pressure receiving area on the atmospheric pressure opening side of the elastic body is provided so as to be smaller than the pressure receiving area on the flow path side.

When the working pressure of the working fluid rises above the reference pressure, the elastic body is deformed so as to enter the atmospheric pressure opening portion, so that the raised fluid pressure is stored as elastic energy and the fluid pressure is lowered. When the fluid pressure drops below the reference pressure, the deformation returns to the original state, and the stored elastic energy is released to the working fluid to compensate for the dropped fluid pressure. As a result, the pulsation of the working fluid can be dampened.

Japanese Unexamined Patent Publication No. 2011-133058

Yasuo SAKURAI et al., "PROPOSAL OF A COMPONENT TO REDUCE PRESSEURE PULSATION IN OIL-HYDRAULIC SYSTEM", The 10th JFPS International Symposium, Japan 20th JFPS International Symposium, 20th Year of Japan Misaki Hashimoto et al., "Improvement of Pressure Pulsation Reduction Element for Hydraulic Systems and Proposal of Mathematical Model", Proceedings of Fluid Power System Lecture, Japan Fluid Power Systems Society, 2019, Autumn 2019, p. 43-45

In the conventional pulsation damping device, the working pressure of the working fluid is usually higher than the atmospheric pressure, so that the elastic body is elastically deformed from the initial stage due to the differential pressure. Therefore, the higher the fluid pressure required to drive the fluid power system, that is, the higher the reference pressure, the wider the difference between the fluid pressure and the atmospheric pressure, and the larger the initial elastic deformation. It ends up. As a result, there is a problem that the excess elastic energy capacity of the elastic body that can be used for pulsation absorption is reduced.

At first glance, for example, if the atmospheric pressure opening is a pressure chamber and the pressure in the pressure chamber is adjusted to be higher than the atmospheric pressure according to the working pressure of the working liquid, this problem can be solved. It seems like, but while it is necessary to seal the high-pressure gas in the gas chamber, it is difficult to avoid the outflow of gas from the pressure chamber, so in order to maintain its function, the pressure chamber should be regularly used. Another problem arises that maintenance is required.

Therefore, an object of the present invention is to provide a pulsation damping device capable of increasing the excess elastic energy capacity of an elastic body that can be used for pulsation absorption.

The present invention is a pulsation damping device for a fluid pressure circuit, wherein an internal flow path forming a part of the fluid pressure circuit, a fluid pressure chamber provided at a position facing the internal flow path, and the internal flow. An elastic body provided so as to separate the path from the fluid pressure chamber is provided, and the fluid pressure chamber is provided so that a pressurized fluid can communicate with the fluid pressure circuit, and the elastic body is provided. It is characterized in that fluid pressure can be received from each of the internal flow path and the fluid pressure chamber, and an area difference is provided between the flow path side pressure receiving area and the fluid chamber side pressure receiving area. It is a pulsation damping device.

Further, the present invention is a pulsation damping device for a fluid pressure circuit, wherein an internal flow path forming a part of the fluid pressure circuit, a fluid pressure chamber provided at a position facing the internal flow path, and the like. An elastic body provided so as to separate the internal flow path and the fluid pressure chamber is provided, and the fluid pressure chamber allows the pressurized fluid to communicate with an external flow path through which the pressurized fluid flows. The elastic body is provided so that the fluid pressure can be received from each of the internal flow path and the fluid pressure chamber, and an area difference is provided between the flow path side pressure receiving area and the fluid chamber side pressure receiving area. It is a pulsation damping device characterized by being used.

The present invention is a pulsation damping device for a fluid pressure circuit, wherein an internal flow path forming a part of the fluid pressure circuit, a fluid pressure chamber provided at a position facing the internal flow path, and the like. It is provided with an elastic body provided so as to separate the internal flow path and the fluid pressure chamber, and a storage portion provided so as to be able to store the working liquid, and the fluid pressure chamber is provided between the storage portion. The working fluid is provided so that it can communicate with each other.
The storage unit stores the working liquid so that the liquid level of the working liquid in the storage part is higher than the liquid level of the working liquid in the fluid pressure chamber, and the elastic body is the internal flow path. The pulsation damping device is characterized in that the fluid pressure can be received from each of the fluid pressure chambers, and an area difference is provided between the flow path side pressure receiving area and the flow path side pressure receiving area. ..

The present invention further includes a side passage, and the working fluid or the pressurized fluid can communicate with the fluid pressure chamber and the external flow path via the side passage. Can be provided in. Further, in the present invention, the side passage can be provided on the downstream side of the elastic body of the internal flow path. Further, in the present invention, it is possible that the side road has a fluid resistance portion. Further, in the present invention, the fluid resistance portion can be provided as a throttle tube. Further, in the present invention, the pressure receiving area on the flow path side can be made larger than the pressure receiving area on the flow path side.

Further, the present invention further includes a pulsation damping chamber, the fluid pressure chamber can be provided in the pulsation damping chamber, and the elastic body can be fitted in the pulsation damping chamber. be. Further, in the present invention, the internal flow path is composed of at least an upstream side flow path, a damping chamber flow path, and a downstream side flow path, and the side path is provided in the downstream side flow path to provide the attenuation. It is possible that the indoor flow path is provided in the pulsation damping chamber, and the elastic body is fitted in the pulsation damping chamber so as to separate the fluid pressure chamber and the damping chamber flow path. ..

The present invention provides a fluid pressure chamber provided so that a pressurized fluid or a working fluid can communicate with a fluid pressure circuit, an external flow path or a storage portion, and an elastic body is formed of the fluid pressure chamber and the flow path. Since the fluid pressure can be received from each, it is possible to increase the excess elastic energy capacity of the elastic body that can be used for pulsation absorption.

It is a vertical sectional view of the 1st Embodiment of this invention. It is the schematic which shows the state of the pulsation of a working fluid. It is a vertical sectional view of the 2nd Embodiment of this invention. It is a vertical sectional view of the 3rd Embodiment of this invention.

The first embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, the configuration of this embodiment will be described. The pulsation damping device 1 is provided in the fluid pressure circuit to dampen the pulsation of a fluid pressure circuit, for example, a fluid pressure system of various fluid power systems that drives a mechanical device using a working fluid which is an example of a pressurized fluid. The internal flow path 2, the fluid pressure chamber 3, the elastic body 4, and the side passage 5 are provided. In the present embodiment, the pulsation damping device 1 further includes a pulsation damping chamber 6. The working fluid may be either a liquid such as water or oil or a gas such as air.

The internal flow path 2 constitutes a part of the fluid pressure circuit, and for example, a working fluid pressurized by a pressurizing means such as a positive displacement pump (not shown) is provided so as to be able to flow. In the embodiment, it is composed of an upstream side flow path 2A, a damping chamber flow path 2B, and a downstream side flow path 2C.

The fluid pressure chamber 3 is provided at a position facing the internal flow path 2 (in the present embodiment, the damping chamber flow path 2B) and is provided so that the working fluid can communicate with the fluid pressure circuit. There is. In the present embodiment, the fluid pressure chamber 3 is provided so that the working fluid can flow between the fluid pressure chamber 3 and the internal flow path 2 via the side passage 5. The connection position between the fluid pressure chamber 3 and the fluid pressure circuit can be appropriately selected as needed, and may be the downstream flow path 2C as described later, or another location (upstream) of the internal flow path 2. It may be a side flow path 2A or a damping chamber flow path 2B), or a flow path directly connected to the outside of the pulsation damping device 1, for example, the upstream side flow path 2A or the downstream side flow path 2C (not shown). Alternatively, it may be a return flow path (not shown) for returning the working fluid to a tank (not shown) or the like in which the working fluid is stored.

As a result, at the time of static pressure, the fluid pressure in the fluid pressure chamber 3 becomes substantially the same as the fluid pressure of the fluid pressure circuit. Further, when the working fluid is flowing in the fluid pressure circuit (internal flow path 2), the fluid pressure in the fluid pressure chamber 3 is pressure loss due to the working liquid flowing through the side passage 5 and the like. Is generated, so that the fluid pressure is attenuated by the amount of the pressure loss, but is synchronized with the fluid pressure in the fluid pressure circuit.

In the present embodiment, the side passage 5 is provided on the downstream side of the elastic body 4 of the internal flow path 2, that is, on the downstream side flow path 2C, and minute fluctuations in fluid pressure in the fluid pressure circuit are caused. In the present embodiment, which has a flow path resistance portion for preventing transmission to the fluid pressure chamber 3, the flow path resistance portion is provided as a throttle pipe 7, and the throttle pipe 7 is a side path. 5 is provided at the end of the internal flow path 2 on the side. The fluid resistance portion is appropriately provided as needed.

By doing so, in the present embodiment, when the working fluid is flowing in the internal flow path 2, the fluid pressure in the fluid pressure chamber 3 is the downstream side flow path 2C in which the pulsation is attenuated. Further, the influence of a minute pressure change in the downstream flow path 2C on the fluid pressure in the fluid pressure chamber 3 is made as small as possible by the throttle tube 7.

The elastic body 4 separates the internal flow path 2 and the fluid pressure chamber 3 so that the fluid pressure can be received from both the internal flow path 2 and the fluid pressure chamber 3, and the pressure receiving on the internal flow path 2 side thereof. area S _{1 (hereinafter,} the flow of the roadside receiving area S ₁₎ is pressure-receiving area S ₂ of the fluid pressure chamber 3 side _{(hereinafter,} referred to as the fluid pressure chamber side pressure-receiving area S ₂₎ differential area is provided between the In this embodiment, the pressure receiving area S _{1 on the} flow path side> the pressure receiving area S ₂ on the fluid pressure chamber side is provided. The ratio of the flow path side pressure-receiving area S ₁ and the fluid pressure chamber side pressure-receiving area S ₂ are suitably selected as required.

The pulsation damping chamber 6 is provided to damp the pulsation of the fluid pressure of the working liquid flowing in the internal flow path 2, and the fluid pressure chamber 3 and the damping chamber flow path 2B are provided. Further, in the pulsation damping chamber 6, an elastic body 4 is fitted so as to separate the fluid pressure chamber 3 and the internal flow path 2 (in this embodiment, the damping chamber flow path 2B). That is, in the present embodiment, the side road 5 is provided on the downstream side of the pulsation damping chamber 6.

In the present embodiment, the pulsation damping chamber 6 is formed as a space having a substantially bottle-shaped cross section in which the neck is located on the opposite side of the internal flow path 2, and the fluid pressure chamber 3 is located in the neck portion where the diameter is narrowed. Is provided. As a result, the pressure receiving area S _{1 on the} flow path side> the pressure receiving area S ₂ on the fluid pressure chamber side. Further, in the pulsation damping chamber 6, the damping chamber flow path 2B is connected to the upstream side flow path 2A and the downstream side flow path 2C via the connection paths 8 and 9.

Next, the pulsation damping step in this embodiment will be described.

(1) First, the pulsation damping device 1 is stationary with its internal flow path 2 and fluid pressure chamber 3 filled with a working fluid. At this time, the internal flow path 2 and the fluid pressure chamber 3 have substantially the same pressure as the _{reference pressure P 0,} and there is a difference between the _{flow path side pressure receiving area S 1} and the fluid pressure chamber side pressure receiving area S _2. The elastic body 4 is elastically deformed and enters the fluid pressure chamber 3 side.

(2) When the pressurizing means is driven, the working liquid is pressurized and flows, and the fluid pressure in the fluid pressure chamber 3 theoretically _changes from the reference pressure P0 of the working liquid to the side road 5 and the like. The pressure loss caused by the flow of the working fluid is held at a pressure approximately equal to the reduced pressure, and the elastic body 4 further elastically deforms and enters the fluid pressure chamber 3 side by the amount of the pressure loss. Will be there.

(3) The fluid pressure of the working fluid pulsates between the upper pulsating pressure P ₁ and the lower pulsating pressure P _{2 due to factors such as the driving of the pressurizing means (Hp 1 in} FIG. 2). reference). When the fluid pressure of the working fluid _{rises from the reference pressure P 0} toward the upper pulsating pressure P ₁ , the fluid pressure in the internal flow path 2 (in the present embodiment, the damping chamber flow path 2B) becomes in the fluid pressure chamber 3. Since the pressure is higher than the fluid pressure of the above, the elastic body 4 is further deformed and enters the fluid pressure chamber 3. At this time, part of the fluid pressure of the working fluid is converted into elastic energy in the elastic body 4 storage, the fluid pressure of the working fluid, so that the closer to the reference pressure P _0.

On the contrary, when the fluid pressure of the working fluid _{drops from the reference pressure P 0} toward the lower pulsating pressure P ₂ , the fluid pressure in the internal flow path 2 (in the present embodiment, the dampening chamber flow path 2B) becomes fluid. Since the pressure becomes lower than the fluid pressure in the pressure chamber 3, the elastic body 4 exerts a restoring force to restore the original shape, and the elastic energy stored in the elastic body 4 is reconverted into the fluid pressure. , The fluid pressure of the working fluid approaches the _{reference pressure P 0.} By repeating this, the fluid pressure of the working fluid is _{maintained near the reference pressure P 0} , and the pulsation is attenuated ( _{see Hp 2 in} FIG. 2).

At this time, since the _{area difference is provided between the flow path side pressure receiving area S 1} and the fluid pressure chamber side pressure receiving area S ₂ , the elastic body 4 responds to a minute pressure change in the internal flow path 2. It is possible to respond quickly.

Therefore, in the present embodiment, unlike the flow path and the atmospheric pressure opening portion of the conventional pulsation damping device, even if the required fluid pressure of the working fluid, that is, the reference pressure P ₀ becomes high, it is theoretically static. Since there is no difference in fluid pressure between the internal flow path 2 and the fluid pressure chamber 3 at the time of pressure, it is possible to reduce the influence on the elastic deformation of the initial elastic body 4 due to the rise of the _{reference pressure P 0.} Is. Therefore, it is possible to increase the excess elastic energy capacity of the elastic body that can be used for pulsation absorption.

A second embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the first embodiment is that the fluid pressure chamber 10 is provided instead of the fluid pressure chamber 3. The configuration shown by the same reference numerals as those of the first embodiment is the same as that of the first embodiment, and thus the description thereof will be omitted.

The fluid pressure chamber 10 of the present embodiment is provided outside the fluid pressure circuit and has an external flow path D through which a pressurized fluid flows, for example, a gas such as a water supply or a pressurized air through which pressurized water flows. The pressurized fluid is provided so as to be able to communicate with the airline in the factory where the pressurized fluid is distributed. In the present embodiment, the fluid pressure chamber 10 is provided so that the external flow path D and the pressurized fluid can communicate with each other via the side passage 11. The side road 11 can adopt the same configuration as the side road 5 of the first embodiment, and may have a fluid resistance portion such as the throttle pipe 7.

In the present embodiment, the fluid pressure in the fluid pressure chamber 10 is about the same as the fluid pressure in the external flow path D, although there is a pressure loss when the pressurized fluid passes through the side passage 11 or the like. .. Since the fluid pressure in the external flow path D is higher than that of the atmospheric pressure due to the pressure of the flowing fluid, the internal flow path 2 and the fluid pressure chamber are higher than those of the conventional pulsation damping device. The difference in fluid pressure from that of 10 becomes small, and it is possible to suppress the elastic deformation of the initial elastic body 4. Therefore, it is possible to increase the excess elastic energy capacity of the elastic body that can be used for pulsation absorption.

A third embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the first embodiment is that the fluid pressure chamber 12 is provided instead of the fluid pressure chamber 3. The configuration shown by the same reference numerals as those of the first embodiment is the same as that of the first embodiment, and thus the description thereof will be omitted.

In the present embodiment, the pulsation damping device 1 further includes a storage unit 13. The fluid pressure chamber 12 of the present embodiment is provided so that the working liquid F stored in the storage unit 13 can communicate with the storage unit 13. The working liquid F is stored in the storage unit 13 so that the liquid level L ₂ is higher _{than the liquid level L 1 of the working liquid F in the fluid pressure chamber 12.}

As a result, in the present embodiment, the hydraulic pressure of the working liquid F in the fluid pressure chamber 12 is equal to the difference ΔL _{between the liquid levels L 1} and L ₂ of the working liquid F between the storage unit 13 and the fluid pressure chamber 12. Is higher than the atmospheric pressure, and therefore, the difference in fluid pressure between the internal flow path 2 and the fluid pressure chamber 12 is smaller than that of the conventional pulsation damping device. It is possible to suppress elastic deformation. Therefore, it is possible to increase the excess elastic energy capacity of the elastic body that can be used for pulsation absorption.

Although the present invention has been described based on the above-described embodiment, the present invention is not limited to the above-described embodiment and can be appropriately modified without changing the gist of the present invention.

(1) The elastic body 4 may be arranged in the internal flow path 2 without providing the pulsation damping chamber 6. Further, the shape of the internal flow path 2 can be appropriately selected, and the internal flow path 2A, the attenuation chamber flow path 2B, and the downstream side flow path 2C can be provided as one straight pipe without being divided.

(2) It is also possible to set the _{flow path side pressure receiving area S 1} <fluid pressure chamber side pressure receiving area S _2. In this case, the fluid pressure in the fluid pressure chambers 3 and 10 at the time of static pressure can be made smaller than the fluid pressure in the internal flow path 2. It is also possible to provide a depressurizing means between the fluid pressure chambers 3 and 10 and the fluid pressure circuit or the external flow path D.

(3) A means for providing an area difference between the flow path side pressure receiving area S ₁ and the fluid pressure chamber side pressure receiving area S ₂ can be appropriately selected, and the internal flow path 2 and the fluid pressure chamber 3 as in the above embodiment can be appropriately selected. , 10 may be narrowed down, but the shape of the elastic body 4 may be changed in shape and area of the upper bottom surface and the lower bottom surface, for example, like a truncated cone.

1 Pulsation damping device 2 Internal flow path 2A Upstream side flow path
2B Damping chamber flow path 2C Downstream side flow path 3 Fluid pressure chamber 4 Elastic body 5 Side road 6 Pulsation damping chamber 7 Squeezing pipe 8 Connecting path 9 Connecting path 10 Fluid pressure chamber 11 Side road 12 Fluid pressure chamber 13 Storage section D External flow Road F Working liquid Hp Fluid pressure L Liquid level P Pressure S Pressure receiving area

Claims (10)

A pulsation damping device for fluid pressure circuits
An internal flow path that forms part of the fluid pressure circuit,
A fluid pressure chamber provided at a position facing the internal flow path,
An elastic body provided so as to separate the internal flow path and the fluid pressure chamber is provided.
The fluid pressure chamber is provided so that the pressurized fluid can communicate with the fluid pressure circuit.
The elastic body can receive fluid pressure from each of the internal flow path and the fluid pressure chamber, and an area difference is provided between the flow path side pressure receiving area and the flow path side pressure receiving area. A pulsation damping device characterized by. A pulsation damping device for fluid pressure circuits
An internal flow path that forms part of the fluid pressure circuit,
A fluid pressure chamber provided at a position facing the internal flow path,
An elastic body provided so as to separate the internal flow path and the fluid pressure chamber is provided.
The fluid pressure chamber is provided so that the pressurized fluid can communicate with an external flow path through which the pressurized fluid flows.
The elastic body can receive fluid pressure from each of the internal flow path and the fluid pressure chamber, and an area difference is provided between the flow path side pressure receiving area and the flow path side pressure receiving area. A pulsation damping device characterized by. A pulsation damping device for fluid pressure circuits
An internal flow path that forms part of the fluid pressure circuit,
A fluid pressure chamber provided at a position facing the internal flow path,
An elastic body provided so as to separate the internal flow path and the fluid pressure chamber,
It is equipped with a storage unit provided so that the working liquid can be stored.
The fluid pressure chamber is provided so that the working liquid can communicate with the storage portion.
The storage unit stores the working liquid so that the liquid level of the working liquid in the storage unit is higher than the liquid level of the working liquid in the fluid pressure chamber.
The elastic body can receive fluid pressure from each of the internal flow path and the fluid pressure chamber, and an area difference is provided between the flow path side pressure receiving area and the flow path side pressure receiving area. A pulsation damping device characterized by. With more side roads
The fluid pressure chamber is provided with the working fluid or the pressurized fluid so as to communicate with the fluid pressure circuit or the external flow path via the side path. 2. The pulsation damping device according to 2. The pulsation damping device according to claim 4, wherein the side path is provided on the downstream side of the elastic body of the fluid pressure circuit. The pulsation damping device according to claim 4 or 5, wherein the side road has a fluid resistance portion. The pulsation damping device according to claim 6, wherein the fluid resistance portion is provided as a throttle tube. The pulsation damping device according to any one of claims 1 to 7, wherein the pressure receiving area on the flow path side is larger than the pressure receiving area on the flow path side. Further equipped with a pulsation damping chamber,
The fluid pressure chamber is provided in the pulsation damping chamber.
The pulsation damping device according to any one of claims 1 to 8, wherein the elastic body is fitted in the pulsation damping chamber. The internal flow path is composed of at least an upstream side flow path, a damping chamber flow path, and a downstream side flow path.
The side road is provided in the downstream side flow path, and is provided.
The damping chamber flow path is provided in the pulsation damping chamber.
The pulsating damping device according to claim 9, wherein the elastic body is fitted in the pulsating damping chamber so as to separate the fluid pressure chamber from the damping chamber flow path. ..

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