JPH0345276B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel high pressure side hose. More specifically, the present invention relates to a high-pressure hose that can prevent noise caused by pulsation by efficiently absorbing pulsation of pressure fluid discharged from a pump of a pressure fluid device.

A pressure fluid device such as a power steering system usually includes a pump 21 that discharges pressure fluid such as pressure oil, a driven device 22 operated by the pressure fluid, and a pump 21 and a driven device 22, as shown in FIG. It consists of a high-pressure side hose 23 and a low-pressure side hose 24 communicating with each other. Hereinafter, a power steering system for an automobile will be described as a representative example of a pressure fluid device.

In a power steering system, a humming noise is generated mainly due to the pulsating pressure of oil discharged from the pump 21 (particularly a positive displacement pump such as a vane pump), and the noise is transmitted into the vehicle interior. As a method of reducing such noise, it is known to use, for example, a pulsation absorbing hose as the high pressure hose (see US Pat. No. 3,323,305).

This pulsation absorption hose consists of a hose that is elastic in the radial direction, and one end of which is fixed to the connection part on the pump outlet side of the hose so as to be concentric with the hose, and extends toward the gearbox side. Its structural feature is that it consists of a spiral tube, and its action is due to the pulsating waves directly transmitted from the pump through the spiral tube, and the inner wall of the hose and the outer wall of the spiral tube. The pulsating waves that are guided in the space toward the pump (i.e., in the opposite direction to the flow direction of the pressure fluid) and reflected at the end of the space on the pump side are removed from the vicinity of the opening end of the spiral pipe (i.e., the gearbox). This is an application of the so-called interference principle.

This product has a complicated internal structure because the spiral pipe and hose are arranged in duplicate, and it is difficult to change the length of the branch pipe once it is assembled. The disadvantage is that it is not possible to change the pulsation frequency of the interfered pulsations, which depends on the weather.

The present invention has been made in view of the above-mentioned drawbacks, and a first connecting fitting for connecting to the discharge port of the pump and a second connecting fitting for connecting to the supply port of the driven device are fixed to both ends respectively. The main control and
A high-pressure side hose consisting of a sub-conduit which is disposed outside the main conduit, one end of which is detachably connected to at least one of the first connection fitting or the second connection fitting, and the other end of which is closed. Since the length of the auxiliary conduit can be easily changed, the pulsation rate to be attenuated can be easily tuned, and versatility can be improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high pressure side hose which is an embodiment of the present invention will be described below with reference to the drawings.

Figures 1 and 2 are front views showing different embodiments of the high pressure side hose of the present invention, Figure 3 is a block diagram of the measuring device, and Figures 4 and 5 are experimental data showing the pulsation absorption effect of the embodiments. .

FIG. 1 shows an embodiment of a high-pressure side hose for power steering. At both ends of the main conduit 1, there are caps 4 for connecting the main conduit 1 and pipes 2 and 3 for connecting to other parts. 5 is caulked and fixed. Pipe 2 is screwed onto block 5. The cap 5, together with the pipe 3 and the cap nut 6, constitutes a second connecting fitting for connecting to a gearbox (not shown). Block 7, together with cap nut 8, pipes 2, 9 and base 4, constitutes a first fitting for connection to a pump (not shown). Furthermore, in block 7,
One end of the sub-conduit 10 is connected to the base 11 and the pipe 12.
It is removably connected. A cap 13 is also fixed to the other end of the sub-conduit 10, and a blind stopper 14 is screwed onto the cap 13. pipe 2, 9, 12
The holes 15 of the block 7, into which the screws are screwed, communicate with each other.

Next, the functions and effects of the high-pressure side hose configured as described above will be explained.

In the high pressure side hose shown in FIG. 1, a pipe 9 is connected to a pump discharge port (not shown) by a cap nut 8, and a pipe 3 is connected to a supply port (not shown) of a gearbox by a cap nut 6. ing.

That is, the pressure oil discharged from the pump flows in the direction of arrow A through pipe 9, block 7, pipe 2, main pipe 1, and pipe 3 in this order. Therefore, since the main pipe 1 is used as it is as a flow path for pressure oil, there is little pressure loss due to flow resistance.

The pulsating waves generated by the pump at this time are
Then, a part of the signal is transmitted into the main conduit 1 and the rest is transmitted into the sub-conduit 10. The pulsating waves transmitted into the auxiliary conduit 10 are transmitted through the blind stopper 14
It is reflected at the position and returns to the block 7 side. This returned pulsating wave and the pulsating wave transmitted to the main pipe 1 interfere with each other and are attenuated.

In the high-pressure side hose of the present invention, the auxiliary conduit 10 is detachably connected to the first connecting fitting or the second connecting fitting, and the auxiliary conduit 10 is arranged outside the main conduit 1, so that the pulsation-absorbing branch hose is Only the auxiliary conduit can be replaced and installed very easily while being integrated into the power steering system. Therefore, even if the pump rotation speed, that is, the frequency of the pulsating wave, differs depending on the car model, it can be easily replaced with an auxiliary conduit with a length that corresponds to the frequency, making it suitable for power steering systems of all car models. It has the advantage that it can be applied to

Further, in the high pressure side hose of the present invention, when the sub conduit 10 is connected to the first connection fitting on the pump discharge port side, the pulsating waves interfered as described above are transmitted to the main conduit 10.
After passing through the inside, it is sent to the gearbox side.
Therefore, the interfered pulsating waves are further attenuated within the main pipe 1, and almost no pulsating waves are transmitted to the gearbox side.

Furthermore, when the auxiliary conduit is connected to the first connection fitting close to the vibration source, there is also the effect that pulsating pressure fluctuations are not transmitted downstream.

Note that a female thread may be provided at the tip of the sub-conduit 10, and the blind plug 14 may be configured to be screwed into the female thread, and by adjusting the screwing depth of the blind plug 14, The substantial length of the sub-conduit 10 (the length of the internal space of the sub-conduit) can be finely adjusted.

Next, the effects of the embodiment will be explained based on experimental data.

Example A nylon braided hose with an outer diameter of 20.7 mm, an inner diameter of 10 mm, and a length of 400 mm is used as the main conduit, and a nylon braided hose similar to the main conduit with a length of 200 mm is used as the sub conduit. A side hose was constructed, and the pulsation absorption effect was measured using the measuring device shown in FIG. The measuring device connects a measuring block _P1 and a measuring block P2 provided at the discharge port of the pump P to the main pipe, applies a load through the throttle valve V, and then connects the measuring block _P1 and the measuring block P2 provided at the discharge port of the pump P to the main pipe. A closed-loop conduit configuration was adopted in which the
After the pulsating pressure was converted into an electrical signal by the converters provided in the measurement blocks _P1 and _P2 , it was amplified by the charge amplifier CH, and analyzed and recorded by the 2-channel FFT analyzer F and the X-Y recorder X.
The measurement conditions at this time were: pump rotation speed 960 rpm;
Load pressure 30Kgf/cm ² and 70Kgf/cm ² , oil temperature 80℃
It was hot.

From the measurement results as described above, the pulsation absorption effect of the example was determined. In Figure 4, the load pressure is 30Kg.
Pulsating pressure fluctuation amount in case of f/cm ² (shown on vertical axis)
It shows the relationship between and the frequency of the pulsating wave (shown on the horizontal axis), where f ₁ is the primary frequency (fundamental frequency) of the pulsating wave, f ₂ is
f ₃ and f ₄ indicate second-order, third-order, and fourth-order frequencies, respectively. FIG. 5 is the same as FIG. 4 except that the load pressure is 70 kgf/cm ² . The amount of pulsating pressure fluctuation of the pump is 316×10 ^-3 Kgf/cm ² for f ₁ and 135× for f ₂
10 ^-3 Kgf/cm ² , 115×10 ^-3 Kgf/cm ² at _f4 .
Therefore, it can be seen that the amount of pulsating pressure fluctuation is significantly reduced in the example. Especially at the primary frequency, the attenuation effect is particularly noticeable.

In this embodiment, the main pipe 1 and the sub pipe 10
are arranged parallel to each other in order to make the overall configuration compact, but depending on the arrangement of peripheral equipment of the high-pressure side hose, for example, as in the embodiment shown in FIG. They may be arranged at right angles to the main pipe 1, and even if they are arranged at any angle, the same pulsation absorbing effect as in the case of parallel arrangement can be achieved.

[Brief explanation of drawings]

Figures 1 and 2 are front views showing different embodiments of the high pressure side hose of the present invention, Figure 3 is a block diagram of a measuring device for measuring the effect of pulsation absorption, and Figures 4 and 5 are of the embodiments. Experimental data showing the pulsation absorption effect. FIG. 6 is a block diagram of the pressure fluid device. (Main symbols on the drawing) 1: Main pipe, 4, 5, 1
1, 13: Base, 7: Block, 10: Sub-conduit,
14: blind plug, 15: hole.

Claims (1)

[Claims] 1 A first connection fitting for connecting to the discharge port of the pump and a second connection fitting for connecting to the supply port of the driven device.
a main pipe having connecting fittings fixed to both ends thereof; and a main pipe arranged outside the main pipe and the first
A high-pressure side hose having one end removably connected to at least one of a connecting fitting or a second connecting fitting, and a sub-conduit whose other end is closed.