JPH0553676B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a steering damper, and in particular,
Regarding a rack-and-pinion type steering damper.

[Conventional technology]

As a rack-and-pinion type steering damper that has been conventionally provided, for example, there is one shown in FIG.

That is, the steering damper has a piston P fixed to a rack shaft A housed in a gear housing H, and a plurality of oil chambers R ₁ and R ₂ partitioned by the piston P are connected to the gear. It is included in the housing H. The piston P is formed with an orifice O that allows communication between the oil chambers R ₁ and R ₂ .

Therefore, when the rack shaft A slides within the housing H due to the transmission of vibrations from the road surface and reaction force from the wheels, for example, when the rack shaft A slides in the direction indicated by the arrow X in the figure, The oil in one oil chamber _R1 defined by the piston P passes through the orifice O and flows into the other oil chamber _R2 .
When passing through this orifice O, a damping effect is exerted,
Road surface vibrations and wheel reaction forces are not directly transmitted to the steering wheel, and therefore, the steering stability of the vehicle can be achieved.

[Problem that the invention seeks to solve]

However, if the structure is as described above, that is, if the combined volume of the oil chambers R ₁ and R ₂ remains unchanged, the oil pressure will change due to expansion and contraction of oil due to changes in oil temperature. There is a problem in that the damping force becomes unstable due to the inability to respond to changes in the amount of oil, as well as changes in the amount of oil due to decreases in oil due to evaporation or leakage, resulting in air being mixed in.

In addition, as a measure to solve the above problem, for example, as shown in Fig. 7, the oil chamber R ₂
Even when forming a hydraulic compensation chamber _R3 that communicates with the inside, the aim is to generate approximately the same damping force when the rack axis A slides in both the direction indicated by the arrow X and the opposite direction. Then, the hydraulic compensation chamber
Gas chamber G behind free piston F that partitions R ₃
In addition to having to seal extremely high-pressure gas inside the steering wheel, high sealing performance is also required at each part, and the improved sealing performance causes an increase in friction, which impairs the steering feel. There is a risk that the

In view of the above-mentioned circumstances, the present invention is capable of dealing with changes in oil pressure caused by expansion and contraction of oil due to changes in oil temperature and changes in oil amount due to decrease in oil due to evaporation and leakage, and also prevents impairing the steering feel. It is an object of the present invention to provide a steering damper with a new configuration that can perform a desired damping action without any problems.

[Means for solving problems]

In order to solve the above problems, the structure of the present invention is such that both sides of the rack shaft are slidably housed in the gear housing through a central piston, and the piston has two oil chambers in the gear housing. In a steering damper that is divided into sections, each oil chamber is communicated with an independent valve unit section formed by connecting a throttle valve and a check valve in parallel, and is also communicated with a hydraulic pressure compensation chamber via each valve unit section. It is characterized by the fact that

〔Example〕

The present invention will be described below based on illustrated embodiments.

FIG. 1 shows a steering damper according to an embodiment of the present invention. A rack shaft 3 has a rack gear part (not shown) that meshes with the pinion gear part 2 and is housed so as to be able to slide in the left and right directions in the figure.
It has.

Note that side rods (not shown) are connected to both ends of the rack shaft 3, which are connected to wheels (not shown). Further, the gear housing 1 is fixed to a vehicle body (not shown).

The gear housing 1 has therein main hydraulic pressures 6, 7 and a sub-oil chamber 8 defined by pistons 4, 5 fixed to the rack shaft 3. That is, inside the gear housing 1 are pistons 4 and 5 fixed to the rack shaft 3.
A plurality of main oil chambers 6, 7 are formed, each being a plurality of oil chambers partitioned by. The main oil chambers 6 and 7 are formed separately and independently so that they are not directly communicated with each other. A sub-oil chamber 8 is formed between 5 and 5.

In the embodiment shown in FIG. 1, the main oil chambers 6 and 7, which are a plurality of oil chambers, are formed separately by the two pistons 4 and 5, but instead of this, As in other embodiments described below,
It goes without saying that it may be divided into sections by one piston 12 (see FIG. 5).

A hydraulic compensation chamber 9 is formed within the rack shaft 3. A gas chamber 11 is located behind the free piston 10 that defines the hydraulic pressure compensation chamber 9, and the gas chamber 11 is filled with high-pressure gas. Therefore, a so-called accumulator is formed within the rack shaft 3.

The oil pressure compensation chamber 9 is communicated with the two main oil chambers 6 and 7 via the sub oil chamber 8, respectively. That is, as shown in FIG. 2, the pistons 4 and 5 are respectively formed with throttle valves 4a and 5a, and the sub oil is supplied from the main oil chambers 6 and 7 through the throttle valves 4a and 5a. The pistons 4 and 5 are formed with check valves 4b and 5b, respectively, and oil is allowed to pass from the sub-oil chamber 8 side to the chamber 8 side through the check valves 4b and 5b. This allows oil to flow toward the main oil chambers 6 and 7. Therefore, the hydraulic pressure compensation chamber 9, that is, the accumulator, is connected to the main oil chambers 6 and 7, which are a plurality of oil chambers, through the throttle valves 4a, 5a and the check valves 4b, 5b, that is, the valve unit section, respectively. It is something that is connected.

Figures 3 and 4 show the principle of the above.
The operation will be explained as follows based on the figure. That is, main oil chambers 6 and 7 which are a plurality of oil chambers
are connected to an accumulator Q, which is a hydraulic pressure compensation chamber 9 that compensates for the temperature and oil pressure of hydraulic oil, through valve unit parts V, respectively, and one oil chamber is opened by sliding of the pistons 4 and 5. For example, if the volume of the main oil chamber 6 is to be reduced, the oil in the one main oil chamber 6 will flow through the throttle valve 4a of one valve unit section V and the check valve 5b of the other valve unit section V. When the hydraulic oil expands due to a rise in oil temperature, etc., and surplus oil that cannot flow into the other main oil chamber 7 appears, the surplus oil It will flow into the accumulator Q.

Conversely, when the pistons 4 and 5 slide so that the volume of the other main oil chamber 7 is narrowed, the oil in the other main oil chamber 7 is drained from the throttle valve of the other valve unit section V. 5a and the check valve 4b of one valve unit section V into one main oil chamber 6.

Therefore, the oil in the main oil chambers 6, 7 alternately moves through the throttle valves 4a, 5a, so that a desired damping force is generated when passing through the throttle valves 4a, 5a, and the oil temperature is Even if there is a surplus amount of hydraulic oil flowing out from each main oil chamber 6, 7 due to a rise in oil temperature, etc., the expansion of the oil due to the rise in oil temperature can be coped with by flowing into the accumulator Q. becomes. Conversely, even if there is a shortage of oil pressure or oil amount due to oil contraction, evaporation, or leakage due to a drop in oil temperature, oil will be replenished from the accumulator Q, and the damping force due to insufficient oil pressure or oil amount will decrease. This also makes it possible to prevent deterioration or inoperability.

Note that the check valves 4c and 5 in series with the throttle valves 4a and 5a in the valve unit section V in FIG.
Reference numeral c indicates check valves 4c and 5a that close the openings of the throttle valves 4a and 5a on the sub-oil chamber 8 side in FIG. may be promoted or omitted. That is, in FIG. 4, for example, when the inside of one main oil chamber 6 is contracted and becomes the high pressure side,
Since no backflow of oil occurs through the throttle valve 4a that communicates with the one main oil chamber 6, the throttle valve 4
The check valve 4c (see FIG. 3) connected in series with the check valve a may be omitted or elevated.

FIG. 5 shows a steering damper according to another embodiment of the present invention. The accumulator Q (see Fig. 3), which constitutes the valve unit section V (see Fig. 3) and the hydraulic compensation chamber 9 (see Fig. 1), is formed outside the gear housing 1. This embodiment differs from the embodiment shown in FIG. 1 in this respect. Hereinafter, the present embodiment will be explained focusing on the differences from the previous embodiments. Note that the same reference numerals used in FIG. 5 as those used in the drawings of the above-mentioned embodiment indicate that the basic configuration is the same. The same applies to

In the steering damper shown in FIG. 5, a plurality of hydraulic main oil chambers 6 and 7 formed in the gear housing 1 are partitioned by one piston 12 fixed to the rack shaft 3. . There is no oil flow between the main oil chambers 6 and 7 via the piston 12. However, the main oil chambers 6 and 7 are connected to a tank T disposed outside the gear housing 1 via passages 13 and 14, and can communicate within the tank T.

As described above, the valve unit section V (see Fig. 3) is disposed inside the tank T, and the valve unit section V is partially fixed to the tank T and the other section is fixed to the tank T. has a base shaft 16 connected to a partition wall 15 fixed to define an accumulator Q (see FIG. 3) in the tank T, and valve disks 17 and 18 are arranged on the base shaft 16 at appropriate intervals. have. and,
The valve disks 17 and 18 are connected to the tank T.
An oil chamber 19 that communicates with the main oil chamber 6 through a passage 13, an oil chamber 20 that communicates with the main oil chamber 7 through a passage 14, and a sub oil chamber that allows communication between the two oil chambers 19 and 20. 8 each form a section.
Furthermore, a passage 21 is formed inside the base shaft 16, one end of which opens into the sub-oil chamber 8, and the other end of which opens into the hydraulic pressure compensation chamber 9.

Furthermore, an accumulator Q is formed in the tank T as described above, and the accumulator Q has a hydraulic compensation chamber 9 defined therein by the partition wall 15. It has a gas chamber 11 behind a free piston 10. And the hydraulic compensation chamber 9
are communicated with the main oil chambers 6 and 7 via the sub oil chamber 8 and oil chambers 19 and 20, respectively.

FIG. 6 shows a more specific embodiment of the tank T, that is, the valve unit section V and the accumulator Q. This embodiment will be briefly described below.

The tank T is formed by sealingly fixing lid members 23 and 24 to both ends of a suitably cylindrical sleeve 22. One end of the base shaft 16 is attached to one lid member 23 by tightening a nut 25. In addition, the other lid member 24 is fitted with a plug 26 for filling gas. A partition wall 15 that partitions the tank T into a valve unit section V and an accumulator Q is fixed to the other end of the base shaft 16 with a nut 27.

Further, the valve discs 17 and 18 disposed on the base shaft 16 are provided with an inner oil passage 28 and an inner oil passage 28, respectively.
29 and outer oil passages 30, 31 are bored.
The leaf valves 32 and 33 corresponding to the throttle valves 4a and 5a (see FIG. 5) are arranged adjacent to the openings of the inner oil passages 28 and 29 on the sub oil chamber 8 side, and the outer oil passages 30, 31 oil chamber 19,
Check valves 4b and 5 arranged adjacent to the opening on the 20 side
It has b.

Incidentally, connectors 34 and 35 are fixed to the outer periphery of the sleeve 22 constituting the tank T and correspond to the outside of the oil chambers 19 and 20. , the main oil chambers 6, 7 (see FIG. 5) and the oil chamber 19,
20 are communicated with each other through passages 13 and 14.

In addition, in this embodiment, when fixing the valve disks 17, 18 to the base shaft 16, spacers 36, 37 that also serve as stoppers and a valve stopper 38 that presses the leaf valves 32, 33 against the valve disks 17, 18 are used. , 39, and in particular, a port 41 is formed in the spacer 40 to allow communication between the passage 21 in the base shaft 16 and the sub-oil chamber 8. It is something.

In any of the embodiments described above, the valve unit portion V is formed within the gear housing 1 or within the tank T, but it may be formed within the rack shaft 3 instead.
Further, the valve unit section V and the accumulator Q may be formed separately inside and outside the gear housing 1, respectively.

〔Effect of the invention〕

As described above, the present invention has the following effects.

Each oil chamber in the gear housing is connected to a hydraulic pressure compensation chamber, so it can cope with oil pressure changes due to oil expansion and contraction due to changes in oil temperature, and can also cope with changes in oil volume due to oil evaporation or leakage. This has the advantage that stable damping force can be obtained.

Since each oil chamber communicates with an independent valve unit, the left and right damping forces can be set freely.

The gas pressure in the gas chamber of the accumulator that constitutes the hydraulic compensation chamber is sufficient to be at the level normally used, so the sealing performance of each part is improved due to the extremely high pressure gas filling, and the steering operation feeling is improved due to the increase in friction, etc. There is no risk of worsening the situation.

If the valve unit and the accumulator are formed outside the gear housing that constitutes the steering damper, this can be used without requiring major design changes to the conventional steering damper, making it more economical. There are also some great advantages.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a steering damper according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the cross section shown in FIG. 1.
FIG. 3 is a circuit diagram showing the principle of the circuit shown in FIG. A diagram showing such a steering damper in the same manner as FIG. 1 and including a partial schematic diagram, FIG. 6 is a sectional view showing more specifically what the schematic diagram in FIG. 5 shows, and FIG. 7 is a diagram showing a conventional steering damper. 2 is a diagram showing a damper in substantially the same manner as FIG. 1; FIG. 1...Gear housing, 3...Rack shaft, 4,
5, 12... Piston, 4a, 5a... Throttle valve,
6, 7...Main oil chamber, 9...Hydraulic pressure compensation chamber, Q...
...Accumulator, T...Tank, V...Valve unit.

Claims (1)

[Claims] 1. Both sides of a rack shaft are slidably housed in a gear housing via a central piston, and the pistons are arranged in a steering damper that divides two oil chambers in the gear housing, respectively. A steering damper characterized in that each of the oil chambers communicates with an independent valve unit section formed by connecting a throttle valve and a check valve in parallel, and also communicates with a hydraulic compensation chamber via each valve unit section. . 2. The steering damper according to claim 1, wherein the valve unit portion and the hydraulic compensation chamber are formed within the gear housing. 3. The steering damper according to claim 1, wherein the valve unit portion is formed in the piston, and the hydraulic compensation chamber is formed in the rack shaft. 4. The steering damper according to claim 1, wherein the valve unit portion and the hydraulic compensation chamber are formed outside the gear housing.