JPH01103574A - High-pressure pipeline for power steering - Google Patents

Abstract

PURPOSE:To abate the extent of frequency pulsating pressure by connecting a rubber hose to a space between a hydraulic pump and an actuator, setting up a steel pipe in the intermediate part, and connecting each of separate rubber hoses to the hydraulic pump side of this steel pipe and the actuator side. CONSTITUTION:In rubber hoses 10, 11, one end clamps a terminal fitting 13 by retightening a socket 12, and a nut 14 is clamped to this terminal fitting 13. The other end of the rubber hose clamps the terminal fitting by retightening the socket 12, and the rubber hose 10 is connected to the rubber hose 11 via a steel pipe 7 fixed to a nipple 13 of the terminal fitting by means of welding or retightening or the like. And the nut at the left is screwed in a high-pressure fluid delivery port of a hydraulic pump, while the nut 14 at the right as faced is screwed in an inlet of an actuator, thereby constituting a high-pressure pipeline for a power steering, If so. an areal expansion value at the time of pressurization of the rubber hose 10 at the hydraulic pump fluid outlet side is altered whereby pulsating pressure at the desired frequency is abatable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high-pressure pipe that is used on the high-pressure side of a power steering system for an automobile and is capable of effectively reducing pulsations during operation.

[Prior Art and Problems] In general, large automobiles have a large weight and therefore require a large steering force. On the other hand, sales of medium-sized and large-sized passenger cars have increased as consumers have become more sophisticated, and cars with power steering devices that allow women and the elderly to drive more easily have become popular.

FIG. 2 is an explanatory diagram of piping for a power steering device of an automobile equipped with a power steering device. In FIG. 2, 1 is a handle, 2 is an actuator, 3 is an engine, 4 is a V-belt, 2 is a hydraulic pump, 6 is a pulsation absorbing rubber hose, 7 is a steel pipe, 8 is a low pressure side rubber hose, and 9 is a reservoir tank. That is, the hydraulic pump 5 is driven by the engine 3 and the V-belt 4 to produce high-pressure fluid, and this high-pressure fluid is sent to the actuator 2 via the pulsation absorbing hose 6 and the steel pipe 7. The high-pressure fluid is used by the actuator 2 to operate the handle, becomes low-pressure fluid, and returns to the reservoir tank 9 of the hydraulic pump 5 via another steel pipe 7. In Fig. 2, a pulsation absorbing rubber hose 6 and a steel pipe 7 are shown.
The piping consisting of is called high pressure piping for power steering equipment. That is, in the high-pressure piping for the power steering device, the inlet side of the pulsation absorbing hose 6 is screwed into the high-pressure fluid delivery port of the hydraulic pump 5.
One end of a steel pipe 7 is connected to the outlet side of the pulsation absorbing hose 6, and the other end is connected to the inlet of the actuator 2.

The length of the copper pipe 7 varies depending on the car model, but is generally 300m.
m to 2,000 mm. Here, the high pressure piping for the power steering device is not constructed only of steel pipes 7 because steel pipes cannot withstand the vibration deterioration peculiar to automobiles and cannot reduce the pulsation of high pressure fluid. On the other hand, if the high-pressure piping for the power steering device is not composed only of the pulsation absorbing hose 6, the piping circuit will be long, and the pulsation absorbing hose 6 will be damaged and deteriorated due to contact with other parts, and furthermore, the pulsation absorbing hose 6 will be long. This is because the pulsation reduction effect is not proportional even if the pulsation is increased, and the cost increases further.

Next, how the pulsating pressure changes depending on the configuration of the high pressure piping will be explained.

3 to 6 are explanatory diagrams showing the configurations of four types of piping used in the pulsation experiment.

That is, Fig. 3 shows a steel pipe with nuts at both ends, Fig. 4 shows a rubber hose with a terminal fitting consisting of a socket 12 and a nipple 13, and a nut attached to it, and Fig. 5 shows a rubber hose with this terminal fitting and a nut attached to one end of the rubber hose on the nipple side. This is a conventional pulsation-absorbing rubber hose made of a fixed flexible metal tube.

FIG. 7 first shows the results of measuring the relationship between frequency and pulsating pressure for these three types.

As can be seen from FIG. 7, the pulsating pressure of the steel pipe 7 is greatest in the range of 100 to 400 H2, which causes noise and vibration. Rubber hose with terminal fittings is 100-300H
Pulsating pressure can be reduced in the range of 2, but 400H2
The pulsating pressure will be greater than that of steel pipes. In contrast, conventional pulsation-absorbing rubber hoses can effectively reduce pulsating pressure over a wide range of 100 to 400 Hz.

However, as mentioned above, the actual high-pressure piping for the power steering system is connected to the high-pressure fluid delivery port of the hydraulic pump 5 and the inlet of the actuator 2 via nuts 14 at both ends of the pulsation-absorbing rubber hose as shown in FIG. It is not intended to connect. That is, the inlet side of a pulsation-absorbing rubber hose with a nut 14 is screwed into one end as shown in FIG. 6 to the high-pressure fluid delivery port of the hydraulic pump 5, and the steel pipe 7 is connected to the outlet side terminal fitting of the pulsation-absorbing rubber hose with a nut 14. Then, at the other end of the steel pipe 7, insert an oak I.1.
4 is fixed, and its nut 14 is screwed onto the inlet side of the actuator 2.

FIG. 8 shows the results of comparing the frequency-pulsation pressure characteristics of the pulsation-absorbing rubber port with the terminal nut shown in FIG. 5 and the conventional high-pressure piping for a power steering device as shown in FIG. 6.

As can be seen from FIG. 8, the pulsation-absorbing rubber hose with a terminal nut on one end and a steel pipe connection on the other end shown in FIG.
There is a drawback that the pulsating pressure near Hz becomes high. This is thought to be because although the pulsation was attenuated in the pulsation-absorbing rubber hose section, the pulsation was induced and re-occurred in the steel pipe section connected to the outlet side.

As mentioned above, conventional high-pressure piping for power steering equipment is not as effective in absorbing pulsating pressure as expected and uses a flexible metal tube inside, so when pressure is applied repeatedly, There is also a risk of damaging the inner surface of the rubber hose, and improvements to this problem have been sought.

[Objective of the Invention] The present invention aims to solve the above-described drawbacks of the prior art and provide high-pressure piping for a power steering device that can reduce pulsating pressure over a wide frequency range without using a flexible metal tube. That is.

[Summary of the Invention] That is, the gist of the present invention is that a hydraulic pump is connected between a hydraulic pump and an actuator, a steel pipe is arranged in the middle, and separate pipes are provided on the hydraulic pump side and the actuator side of the steel pipe. The high pressure piping for the power steering device is connected to a rubber hose, and by arranging the rubber hoses at both ends, it is possible to reduce the pulsating pressure at the desired frequency.

In the present invention, the rubber hose may be any material that can be used as a high-pressure hydraulic hose; for example, an oil-resistant rubber tube is arranged in the inner layer, a braided reinforcing layer is provided in the upper layer, and the upper layer is provided with a weather-resistant, mechanical A typical example is one provided with an outer rubber layer with excellent properties.

Further, in the present invention, the rubber hoses are connected by a steel pipe, and the steel pipe in this case is directly fixed to the end fitting of the rubber hose.

In the high-pressure piping for a power steering device according to the present invention, if the length of the rubber hose and steel pipe is long, it is recommended to provide an intermediate locking part between the rubber hose or the steel pipe as necessary to lock it to the vehicle body. good.

[Example] The present invention will be explained below based on examples.

FIG. 1 is a longitudinal sectional view showing an embodiment of high pressure piping for a power steering device according to the present invention.

In FIG. 1, 10 is a rubber hose on the high-pressure fluid delivery port side of the hydraulic pump, and 11 is a rubber hose on the inlet side of the actuator. At this time, the amount of volumetric expansion of the rubber hose 10 when pressurized is smaller than that of the rubber hose 11.

Further, 12 is a socket of the terminal fitting, 13 is a nipple of the terminal fitting, 14 is a nut, and 7 is a steel pipe.

At one end of the rubber port 10.11, a terminal fitting is fixed by crimping the socket 12, and a nut is fixed to the terminal fitting. A terminal fitting is fixed to the other end of the rubber hose by crimping a socket 12, and a steel pipe 7 is fixed to a nipple 13 of the terminal fitting by welding or crimping.
The rubber port 10 and the rubber hose 11 are connected through the rubber port 10 and the rubber hose 11.

The nut 14 on the left side of FIG. 1 is screwed into a high-pressure fluid delivery port of a hydraulic pump, and the nut 14 on the right side is screwed into an inlet of an actuator to form high-pressure piping for a power steering device. As described above, in this embodiment, two independent rubber hoses 10 and 11 are connected by a steel pipe 7.

FIG. 9 shows the high pressure piping for a power steering device according to the present invention constructed as described above, the rubber hose shown in FIG. 4 as a comparative example thereof, the conventional pulsation absorbing rubber hose shown in FIG. 5, and the conventional pulsation absorbing rubber hose shown in FIG. This figure shows the results of measuring the frequency-pulsating pressure characteristics of a conventional high-pressure pipe for a power steering device.

As is clear from FIG. 9, the pulsating pressure of the rubber hose in FIG. 4 is the highest, and almost no reduction effect can be seen. 6th
The conventional high-pressure piping for a power steering device shown in the figure is not as effective in reducing pulsating pressure as expected. The conventional pulsation-absorbing rubber hose shown in FIG. 5 has a considerable effect of reducing pulsating pressure, but around 100H2 and 28082, the effect of reducing pulsating pressure is not so great. On the other hand, it can be seen that the high pressure piping for a power steering device according to the present invention has the smallest pulsating pressure over 120 to 400 H2, and has excellent pulsating absorption characteristics.

Figure 10 shows the relationship between frequency and pulsating pressure measured using rubber hoses with different volumetric expansions when pressurized as shown in Table 1 as the rubber hose 10 on the high-pressure fluid delivery port side of the hydraulic pump according to the present invention. FIG. 3 is a diagram showing the results. As can be seen from FIG. 10, the pulsating pressure at a desired frequency can be reduced by changing the amount of volumetric expansion during pressurization of the rubber hose 10 on the high-pressure fluid delivery port side of the hydraulic pump.

Table 1 Note that the example shows the case where two rubber hoses are used, but when the piping is configured by combining not only two but three or more rubber hoses, when pressurizing each rubber hose, It was also confirmed through other experiments that optimal pulsation absorption characteristics can be obtained by changing the amount of volumetric expansion.

[Effects of the Invention] As described above, the high-pressure piping for a power steering device according to the present invention has excellent pulsation absorption characteristics over a wide frequency range, and the piping work can be done by combining a rubber hose and a steel pipe. As a result, short piping, long piping, bent piping, etc. can be freely realized, and this has great industrial significance.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the high pressure piping for a power steering device of the present invention, Fig. 2 is an explanatory diagram of the piping for a power steering device of an automobile equipped with a power steering device, and Fig. 3 is a terminal Figure 4 shows a rubber hose with a terminal nut and a terminal joint.
FIG. 5 is a vertical sectional view of a conventional pulsation-absorbing rubber hose in which a visible metal tube 13 is crimped and fixed to the nipple 13 on one end joint side of the rubber hose with the end nut and end joint shown in FIG. The figure shows the conventional high-pressure piping for power steering equipment in which steel pipe 7 is connected to the conventional pulsation-absorbing rubber hose shown in Fig. 5, and Fig. 7 shows the relationship between frequency and pulsating pressure for each of the configurations shown in Figs. 3 to 5. Measured diagram, No. 8
The figure is a graph comparing the frequency-pulsating pressure characteristics of the rubber hose shown in Fig. 5 and the conventional high pressure piping shown in Fig. 6, and Fig. 9 is a diagram comparing the high pressure characteristics for a power steering device according to an embodiment of the present invention. Frequency-pulsation pressure diagram for four types of piping and rubber hose shown in Figure 4, conventional pulsation-absorbing rubber hose shown in Figure 5, and conventional high-pressure piping for power steering device shown in Figure 6, Figure 10
The figure is a graph showing the relationship between frequency and pulsating pressure when the volumetric expansion amount during pressurization of the rubber hose on the high-pressure fluid delivery port side of the hydraulic pump is changed in an embodiment of the present invention. 7: Steel pipe, 10.11: Rubber pose. Agent Patent Attorney Fujio Sato Mae f Figure 2rgJ 2 ? Ri Chie 1-ta-sa 4 figure 15r3! Previous 6 (3, +s 'g
4g. River cicada (Hz)

Claims (3)

[Claims] (1) A power supply pipe connected between a hydraulic pump and an actuator, with a steel pipe arranged in the middle, and separate rubber hoses connected to at least the hydraulic pump side and the actuator side of the steel pipe, respectively. High pressure piping for steering equipment. (2) The high-pressure piping for a power steering device according to claim 1, wherein the respective rubber hoses have different expansion amounts when pressurized. (3) A high-pressure pipe for a power steering device according to claim 1 or 2, wherein a locking member is provided in the middle of the pipe.