JPH02309095A - Pulsation absorbing pipe - Google Patents

Abstract

PURPOSE:To suppress the pulsation of a fluid at the time of merging by providing a pulsation absorbing member consisting of a center pipe section forming a center passage and bulkhead sections forming spiral passages on the outer periphery of the center pipe section in the hole of an outer cylinder. CONSTITUTION:A pulsation absorbing pipe is formed with an outer cylinder 1 and a pulsation absorbing member 2. The outer cylinder 1 is a rubber hose, and it is formed with a hose main body 10 with a hose hole 10a and a reinforcing layer 11. The pulsation absorbing member 2 is made of rubber, and it is formed with a center pipe section 21 forming a center passage 20 and four spiral bulkhead sections 23 forming four spiral passages 22. The pulsation absorbing member 22 is inserted into the outer cylinder 1, and spiral passages 22 are formed between the inner periphery of the hose hole 10a and the outer periphery of the center pipe section 21 at the preset pitch. The pressure phase of a fluid can be changed, and the pulsation of the fluid such as oil generated on the inlet side can be damped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulsation absorbing tube that suppresses pulsation of fluid. This pulsation absorbing tube can be used, for example, to attenuate hydraulic pulsations generated in a hydraulic circuit such as a power steering system, and to attenuate sound transmitted through liquid.

[Prior Art] Conventionally, for example, in a pulsation absorbing tube used to absorb hydraulic pulsations generated in a hydraulic power source, as shown in FIG. One is known that includes a hollow inner tube section 301 and a shielding wall 302 that blocks a space between the outer circumferential surface of the inner tube section 301 and the inner circumferential surface of the outer tube section 300. In this pulsation absorbing tube, when oil flows from the inlet side to the outlet side of the pulsation absorbing member, the blocking wall 30
In step 2, a phenomenon occurs in which oil is reflected. Therefore, the oil flowing from the inlet side to the outlet side of the pulsation absorbing member and the shielding wall 30
The oil reflected in step 2 interferes. Therefore, even if hydraulic pulsation occurs on the inlet side of the pulsation absorbing tube, the pulsation can be suppressed.

[Problems to be Solved by the Invention] The present invention is directed to the inner circumferential surface of the outer tube portion 300 and the inner tube portion 301 described above.
Unlike the method of reflecting oil with a shielding wall 302 that shields the space between the outer peripheral surface of It is an object of the present invention to provide a pulsation absorbing tube that employs a method of suppressing pulsation of fluids at the time of merging.

[Means for Solving the Problems] The pulsation absorbing tube of the present invention includes: an outer tube section; a central tube section that defines a central passage extending from one end to the other end provided in a hole in the outer tube section; and an outer tube section. at least two spiral passages located between the inner circumferential surface of the outer tube section and the outer circumferential surface of the central tube section and extending spirally through the cylindrical space between the inner circumferential surface of the outer tube section and the outer circumferential surface of the central tube section; and a pulsation absorbing member consisting of a partition wall section.

The pulsation absorbing tube of the present invention includes an outer cylinder portion and a pulsation absorbing member. The outer cylindrical portion allows fluid to flow therein, and may be a rubber hose, a resin hose, or a metal pipe. The pulsation absorbing member has a central passage extending straight from one end to the other and a spiral passage extending spirally around the central passage, and may be made of rubber, resin, metal, or ceramics. The pitch of the helical passage of the pulsation absorbing member can be appropriately selected depending on the phase of the pulsation of the fluid and the like. The number of pulsation absorbing members disposed in the hole of the outer cylinder portion may be one, or two or more may be disposed in the transverse direction.

The fluid flowing through the pulsation absorbing tube of the present invention may be a liquid such as oil or a gas such as air.

[Function] The function of the pulsation absorption tube of the present invention will be explained together with its usage method. This pulsation absorption tube has one end connected to a high pressure fluid source and the other end connected to an actuator.

In this state, a fluid having a constant pressure phase flows through both the central passage and the spiral passage of the pulsation absorbing member.

Here, at the inlet of the pulsation absorbing member, the pressure phase of the fluid flowing into the central passage and the pressure phase of the fluid flowing into the spiral passage are the same, but the spiral passage has a longer flow path length than the central passage. On the outlet side of the pulsation absorbing member, the pressure phase of the fluid flowing out from the central passage is different from the pressure phase of the fluid flowing out from the spiral passage. Then, they merge again at the outlet of the pulsation absorbing member, and as a result, the resulting pressure phase of the fluid cancels each other out, and the pulsation of the fluid is absorbed.

[Embodiment] A first embodiment in which the pulsation absorbing tube of the present invention is applied to a hydraulic circuit will be described with reference to FIGS. 1 to 4. FIG.

This pulsation absorbing tube is formed of an outer cylindrical portion 1 and a pulsation absorbing member 2.

The outer cylindrical portion 1 is made of a rubber hose, and includes a hose body 10 having a hose hole 10a and a reinforcing layer 11 embedded in the hose body 10.

The pulsation absorbing member 2 is inserted into the hose hole 10a of the outer cylinder portion 1 and held therein. The pulsation absorbing member 2 is made of rubber, and as shown in FIG. 2, it has a central tube section 21 that defines a central passage 20 extending straight from one end 2a to the other end 2b, and four spiral passages 22. Four spiral partition walls 23
It is formed by. Each spiral passage 22 spirally extends in a cylindrical space between the inner peripheral surface of the hose hole 10a of the outer cylinder part 1 and the outer peripheral surface of the central tube part 21 at a predetermined pitch. In this embodiment, the outer surface 23a of the partition wall 23 of the pulsation absorbing member 2 and the inner peripheral surface of the hose hole 10a of the outer cylinder part 1 are integrally joined, so that the pulsation absorber 2 is attached to the outer cylinder part 1. Retained.

Next, a method for manufacturing the above-mentioned pulsation absorbing tube will be explained.

First, unvulcanized compounded rubber is extruded using an extrusion mold, and the first
A rubber pipe 4 made of unvulcanized rubber and having a constant cross-sectional shape as shown in the figure is formed. This rubber pipe 4 has a central hole 4a extending straight from one end to the other, and four straight fins 4b. and,
A rubber pipe 4 with straight fins 4b is twisted and deformed about its axis. The thus twisted rubber pipe 4 is subjected to a half-load Wt treatment to ensure the stability of its shape. Thereafter, the twisted rubber pipe 4 is inserted into the unvulcanized outer cylinder part 1 made by extruding unvulcanized compounded rubber, and in this state, the rubber pipe 4 and the outer cylinder part 1 are cured by carosulfurization treatment. , thereby making the rubber pipe 4 the pulsation absorbing member 2,
The pulsation absorbing member 2 and the outer cylinder part 1 are integrated.

To use this pulsation absorption tube, proceed as follows. That is, as shown in FIG. 4, the hose hole 1 at the end of the outer cylinder part 1
A nipple 30 is inserted into the inner surface of the outer cylinder 1, and a cylindrical sleeve 31 is attached to the outer surface of the outer cylinder 1. Here, the sleeve 31 is caulked, and the wall portion of the outer cylinder portion 1 is held between the nipple 30 and the sleeve 31.

Then, the pulsation absorption pipe is incorporated into the hydraulic circuit and interposed between the hydraulic pressure source side and the actuator side. In this state, the oil in the hydraulic circuit flows through the hose hole 0a of the outer cylinder part 1.
flowing within. At this time, the oil flowing inside the hose hole 0a is
It flows through both the central passage 20 and the spiral passage 22 of the pulsation absorbing member 2.

The oil flowing through the central passage 20 flows straight, and the oil flows through the spiral passage 22.
The oil flowing through the pipe swirls in a spiral pattern.

Here, when oil with pulsations generated by the hydraulic power source reaches one end 2a which is the inlet of the pulsation absorbing member 2, the central passage 2
The pressure phase of the oil flowing into the spiral passage 22 is the same as the pressure phase of the oil flowing into the spiral passage 22. However, in this embodiment, the spiral passage 22 has a spiral shape and has a longer flow path length than the straight central passage 20. The pressure phase of the oil discharged from the spiral passage 22 becomes different from the pressure phase of the oil discharged from the spiral passage 22. Then, on the other end 2b side which is the outlet of the pulsation absorbing member 2, the oil flowing out from the central passage 20 and the oil flowing out from the spiral passage 22 join and mix. Then,
The merging dampens the oil pressure pulsations. Therefore, noise and imaging caused by hydraulic pulsations can be suppressed.

Although the pulsation absorbing member 2 is made of rubber in the first embodiment, it is not limited to this, and may be formed by extrusion molding of resin. In this case, a thermoplastic resin is extruded to form a pipe with straight fins having the structure shown in FIG. 1, the pipe is twisted when it has plasticity, and then it is cooled and hardened.

A second embodiment of the invention is shown in FIGS. 5-7.

The pulsation absorbing tube of the second embodiment basically has the same structure as the first embodiment, and the following description will focus on the specific parts. That is, as shown in FIG. 6, this pulsation absorbing member 6 includes a central tube portion 61 made of rubber defining a central passage 60 extending straight from one end 6a to the other end 6b, and four spiral passages 62.
four spiral rubber partitions 63 that partition the
It is formed of a partition wall part 63 and an integral outer tube part 64.

In the second embodiment, as shown in FIG. 7, the outer circumferential surface of the outer tube section 64 and the inner circumferential surface of the host hole 10a of the outer tube section 1 are integrally joined. In order to manufacture this pulsation absorbing tube, unvulcanized compounded rubber is extruded using an extrusion mold to form a cylindrical rubber pipe 7 as shown in FIG. The rubber pipe 7 has a central hole 7a extending straight from one end to the other end.
is formed, and a straight wall 7C is formed that partitions a passage 7b extending straight in parallel with the central hole 7a.

Then, the rubber pipe 7 is rotated around the axis of the rubber pipe 7.
Twisting and deforming. Rubber pipe 7 twisted like this
Perform semi-vulcanization treatment to ensure shape stability. Thereafter, as in the case of the first embodiment, the rubber pipe 7 is inserted into the outer cylinder part 1 formed by extruding unvulcanized rubber compound, and in this state, the rubber pipe 7 and the outer cylinder part 1 are vulcanized. harden, thereby making the rubber pipe 7 the pulsation absorbing member 6,
The pulsation absorbing member 6 and the outer cylinder part 1 are integrated.

In the pulsation absorbing tube of the second embodiment, as in the case of the first embodiment, the spiral passage 62 is formed in a spiral shape and has a longer flow path length than the straight central passage 60. end 6
On the b side, the pressure phase of the oil flowing out from the central passage 60 is different from the pressure phase of the oil flowing out from the spiral passage 62. Therefore, when the oil flowing out from the central passage 60 and the oil flowing out from the spiral passage 62 meet and mix on the other end 6b side, which is the outlet side of the pulsation absorbing member 6, the pulsations in the oil pressure are attenuated. be done.

[Effects of the Invention] According to the pulsation absorption tube of the present invention, since the spiral passage is spiral and has a longer flow path length than the straight central passage, the pressure phase of the fluid discharged from the central passage, The pressure phase of the fluid discharged from the spiral passage can be made different. Therefore, since the fluids having different pressure phases join together at the outlet side of the pulsation absorbing member, it is advantageous for damping the pulsation of fluid such as oil generated at the inlet side of the pulsation absorbing tube.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a perspective view of a pipe with straight fins, FIG. 2 is a perspective view of a pulsation absorbing member, and FIG. 3 is a main part of a pulsation absorbing pipe. Perspective view showing part 4
The figure is a cross-sectional view of the main parts showing the usage state of the pulsation absorbing tube. 5 to 7 show a second embodiment of the present invention, FIG. 5 is a perspective view of a pipe with straight fins, FIG. 6 is a perspective view of a pulsation absorbing member, and FIG. 7 is a use of a pulsation absorbing pipe. It is a sectional view of the main part showing the state. FIG. 8 is a sectional view showing the main parts of a conventionally used pulsation absorbing tube. In the figure, 1 is an outer cylinder part, 2 is a pulsation absorbing member, 20 is a central passage, 21 is a central tube part, 22 is a spiral passage, and 23 is a partition part. Patent applicant: Tokai Gomue, agent of Gyo Co., Ltd.
Patent Attorney Hiroshi OkawaFigure 5Figure 6Figure 8

Claims (1)

[Claims] (1) An outer cylinder part, a central pipe part provided in a hole of the outer cylinder part that defines a central passage extending from one end to the other end, an inner peripheral surface of the outer cylinder part, and an outer periphery of the central pipe part. A pulsation absorbing device comprising a partition wall located between the surfaces and dividing a cylindrical space between the inner peripheral surface of the outer cylinder part and the outer peripheral surface of the central pipe part into at least two spiral passages extending spirally. A pulsation absorption tube characterized by having a member.