JPH01319590A - Hydraulic oil for motorcar excellent in hydraulic responsibility - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention provides a hydraulic fluid for automobiles, particularly a hydraulic device that uses sap fluid to control the attitude of an automobile. The present invention relates to a hydraulic fluid for automobiles which has excellent hydraulic responsiveness and is applied to hydraulic fluids that enable accurate attitude control. This invention relates to a hydraulic fluid for automobiles that has excellent oil-based hydraulic response.

(Prior art) As a support device for an automobile body, a hydraulic ram is installed in place of a spring tapper near the four wheels. Some people try to control the posture of the vehicle stably by driving the vehicle.

Hydraulic fluids used for this type of applications have basic characteristics, taking into account the environment in which they are used in automobiles, particularly good viscosity properties on the high-temperature side-C, and good/lower-temperature fluidity properties on the low-temperature side. [2t1 and others are required to have good viscosity-temperature characteristics.

Hitherto, hydraulic fluids based on mineral oil base oils have been known as hydraulic fluids used for this type of applications.
A large amount of polymethacrylate (1-) type viscosity index improver is blended to maintain the above-mentioned viscosity-temperature characteristics. I
Manufactured.

(Problem to be Solved by the Invention) However, in the case of the conventional mineral oil-based hydraulic fluid described above, more specifically, desired viscosity-temperature characteristics can be obtained! First, add a large amount of 1) IA as a viscosity index improver to mineral oil with a viscosity of about 2 centimeters (1 () 0 °C).
<I) Normal automobile hydraulic fluid, such as automatic transmission flute (automatic transmission fluid), which is used for hydraulic operation. Used to engage wet-type multi-purpose clutches. ), the flash point of PSE (power steering flute, which is used to assist the steering force by hydraulically activating the power screw) is 200°C or higher, whereas ~14 Fl
(11) The evaporation loss reaches 15 to 35%, whereas it is almost 0% in PSF, (ii)
i) Low basic viscosity, poor seizure resistance (1v) Shear stability, i.e. low viscosity stability of hydraulic oil due to shear force (1v1 moving parts of piston pumps, shock) d3 to the nozzle of the absorber screw
However, the viscosity is low due to shear force, which is mainly due to the low shear stability of the polymer @P crystal. ), 4 [Which drawbacks do you have? That is, it is insufficient in maintaining the crystalline state of the hydraulic oil over a long period of time, especially in terms of maintaining hydraulic responsiveness.

The present invention solves the drawbacks of the above-mentioned mineral oil-based hydraulic fluid for automobiles, and provides a synthetic lubricating oil system, particularly a silicone-based hydraulic fluid and an ester-based hydraulic fluid based on a base oil, for use in automobiles with excellent hydraulic response. The purpose is to provide hydraulic fluids.

(Structure of the Invention) (Means for Solving the Problems) To summarize the present invention, the present invention comprises a silicone-based hydraulic fluid and an ester-based hydraulic fluid, and further includes an anti-wear agent or the like. The present invention relates to a hydraulic fluid for automobiles which is characterized by containing a lubricating oil additive and has excellent hydraulic responsiveness.

Hereinafter, the configuration of the present invention will be explained in detail.

As mentioned above, the automotive hydraulic oil of the present invention is particularly applicable to a hydraulic system that uses hydraulic pressure to control the attitude of a vehicle body in place of the suspension paddle that uses a conventional streaking damper. 1゜In this type of attitude control, with the development of sensor technology, road surface information is manually collected by sensors or thousands of pieces per second, for example, 3000 pieces per second, and posture is controlled in response to this information. or is carried out. Therefore, for accurate attitude control, the hydraulic fluid must respond stably over a long period of time to several thousand times 7 seconds of hydraulic drive instructions.

In addition, the present inventors have determined that the oil I dry hydraulic oil used for this type of use has good viscosity characteristics at high temperatures (night), specifically 5 to 7, considering the conditions of the automobile usage environment. To put it bluntly, we need good low-temperature fluidity on the low-temperature side, specifically viscosity-temperature characteristics of 500 millipascals (mpas) or less (-30°C). It has been found that it is preferable that the viscosity index (V, I) of the base oil is 3()0 or more.

It goes without saying that the basic properties of this type of hydraulic oil must be comprehensively excellent in flammability, evaporation loss, seizure resistance, shear stability, etc., as mentioned above.

The present invention has been made by blending specific synthetic lubricating oils with better viscosity-temperature characteristics than mineral oils to produce automobile hydraulic fluids having the above-mentioned required performance, namely, silicone-based hydraulic fluids and ester-based hydraulic fluids. It is characterized in that it is constructed by drying the fluid. Also,
The present invention is characterized in that the synthetic lubricating oil blend base oil is blended with a lubricating oil additive that roughly improves the properties of the hydraulic oil.

Each component used in the automotive hydraulic oil of the present invention will be explained in detail below.

The silicone oil used as the silicone-based hydraulic fluid used in the present invention has the following characteristics compared to mineral oil.

(a) It has very good viscosity-temperature characteristics; for example, mineral oil has a high viscosity index of about 120, and silicone oil has a viscosity index of 400 or more.

Therefore, it is not necessary to use a polymer-based viscosity index improver such as mineral oil, and the shear stability is extremely excellent.

(b) Excellent low-temperature fluidity, with a pour point of -5()°C
Required below.

(c) It has excellent heat and oxidation stability, and does not easily generate sludge even when used for a long time.

(d) The surface tension is about 21×10 N/cm, and it wets metal and rubber surfaces more easily than mineral oil (27 to 29×10 N/cm).

The types of silicone oils described above used in the present invention include 1) Orcassilan, 2) Organosyrogisan, and 3)
The ornopolysiloxane is necessarily the one shown below.

1) Orcassilan-8i-R? )ΔLucanosiloxane OROR? R RQ-3i -〇R, RO-31-0-3i -OR
IRδRδR 3) Organopolysilogysan - In Noshiro d3, R is methyl, ethyl, p[1
Indicates a linear or branched alkyl group such as biru, isopropyl, octylbutyl, isobutyl, amyl, isoamyl/yoto. Further, n (average degree of polymerization) is -10 to 100.

Among the above-mentioned silicone oils, those with a phenyl group or a long chain alkyl group on the C6 chain are unfavorable because they reduce the characteristics of silicone oil - viscosity and temperature characteristics.
Those having the following alkyl groups, particularly dimethylbolysilogysan, are preferred.

In addition, in terms of viscosity-temperature characteristics, the viscosity at 100°C is 5
~35 Cendestokes [Hex, preferably 7 to 30 Cendestokes, especially from the viewpoint of oil leakage from the hydraulic pump and wear resistance. On the other hand, the viscosity at -30°C is 10 to 500 mpaS, especially from the viewpoint of low-temperature startability. OOmpaS or less is preferable.

The silicone-based hydraulic fluids described above have excellent viscosity-temperature characteristics or have improved properties of hydraulic fluids such as wear resistance.
The ability to dissolve or disperse additives is insufficient. In d3 of the present invention, this problem is solved by using the following ester-based hydraulic fluid.

The ester-based hydraulic fluids used in the present invention include (a) diester-based fluids, (b) monoester-based fluids,
(c) There is a polyol Nisder type.

(a) Diester-based hydraulic fluid: The diester-based hydraulic fluid used in the present invention is obtained by condensation of an aliphatic dibasic acid having 4 to 9 carbon atoms and an alcohol having 4 to 8 carbon atoms, and is heated to 100°C. It has a viscosity of 1 to 3 CST.

Preferred examples of aliphatic dibasic acids having 4 to 9 carbon atoms include succinic acid, glutaric acid, adipic acid, piperic acid, superric acid, inic acid, and sebacic acid, and among these, particularly preferred are are succinic acid, glutaric acid, adipic acid, piperic acid, and the most preferred is adipic acid.

Among the alcohols having 4 to 8 carbon atoms, preferred ones include n-butanol, isobutanol, []-amyl alcohol, isoamyl alcohol, n-beki-4-nor, 2-ethylbutanol, cyclobeki-4-notol,
n-to1tanol, isoheptatool, methylcyclohegizanol, n-octatool, dimethylhex] dogol, ? Examples include -ethylhexanol, 2,4.4-trimederpentanol, inoctatool, and 3,5.5-1-limethylhexanol, and among these, 2-ethylhexanol is particularly preferred.

Specific examples of the diester hydraulic fluid used in the present invention are listed below.

C(1-ethylpropyl)adipate, D(3-
Methylbutyl)azibe 1~, C(1,3-methylbutyl)adipate 1~, Di(2-ethylhexyl)adipate, C(1-ethylpropyl)acelate, C(3-methylbutyl)azibe 1~, Di(2- Ethylbutyl) acelate, C(2-ethyl I\gyl)
, C(n-butyl)sebakey 1~, G(isobutyl)sebakey 1, Di(1-ethylp1]pyl)sebacate, Z(i,3-methylnodyl)sebakey 1
~, Di(2-methylbutyl) sebake 1~, C(2)
-[-Tylhexyl) Sebake 1~, G [2-(2
-] Nichiruf 1-1) - C) 10 Del] Sebake 1~,
Sea (2, 2, 4-1 ~ rimedil benzil) Sepake 1 ~ etc.

The di]ster-based hydraulic fluid described above has a viscosity of 2 to 33 centistokes, preferably 2.3 to 3.0 centistokes, at 100"C. If it is too low, there will be problems with flash point, volatility and load resistance, and if it is higher than this, the compatibility with silicone oil will be low and the valve head will be damaged.

(b) Monoester-based hydraulic fluid: The Nistyl-based hydraulic fluid used in the present invention has a carbon number of 1.
It is obtained by condensation of an aliphatic basic acid of 2 to 18 carbon atoms with an alcohol of 1 to 4 carbon atoms, and has a viscosity of 1.0 to 2.0 centimeters at 100°C. be.

The aliphatic basic acids include lauric acid, myristic acid, valmitic acid, margaric acid, stearic acid, and A-leic acid, preferably uric acid and Δ-rhein acid.

Examples of the alcohol include methanol, ditanol, dipropanol, isopropanol, butanol, isobutanol, and isopropanol is preferred.

Specific examples of the -L-notch sprue-based hydraulic fluid used in the present invention include methyl laurate, isobutyl myristate,
1 building, etc.

(c) Polyol-[Nistyl-based hydraulic fluid: this (,1
The condensation of a polyol and an aliphatic basic acid yields 15t, such as -C1.

(1) 1 helimethy(2+ -/rev 1) 1 pan J stel 1-rimedirolzo[-] pan and carbon number 4 to 12
Which condensation of an aliphatic-(basic acid) is used to form an ester.

The fatty acids include acetic acid, chirasonic acid, cabroic acid, caprylic acid, lauric acid, etc., and preferably carboxylic acid, caprylic acid, etc.

(11) Pentaerythritol ester Pentaerythritol etc. Carbon number 4'cK used in the above 0) 12
It is obtained by the condensation of the compound with an aliphatic-IA base acid.

The blending ratio (@ volume ratio) of the silicone-based hydraulic fluid and the Esral-based hydraulic fluid described above is -3() to 9/- for boat fishing.
70-5, particularly preferably 50-95,150-5.

In addition, the viscosity of the mixed system of the silicone-based hydraulic fluid and the 2-stellite curved fluid is 30 to 10 centimeters (100°C), particularly preferably 0. to 7.0 centimeters (100°C). On the other hand, the low temperature fluidity is 500ml
)as(-30°C) or less, particularly preferably 30()as(-30°C) or less.

In the present invention, various additives may be added to the Frund base oil of the silicone-based hydraulic fluid and ester-based hydraulic fluid described above in order to improve the properties of the hydraulic fluid.

This type of additive will be explained below.

(1) Anti-wear agent: In the hydraulic fluid of the present invention, 1) Nisdel phosphate and phosphite are used to improve frictional properties and anti-wear properties.

(a) Phosphate esters are used especially to improve initial low friction properties and anti-wear properties.

(b) Phosphite esters are used to ensure particularly low abrasive properties over a long period of time.

As the phosphoric acid compound, for example, the following - Noshiro % formula % (j) Oleyl Ashidov A Sphuni 1 ~ (What is this? 1
-1 C181 mountain Te○-P == 0 and ♂11 (jl) dioleylhydrogunphosnono-i1~((
C1? ! -1. S-0)2 1--0)-1>
etc. are used.

From the viewpoint of their effects, the amount of the phosphoric acid compound used in <1) above is 0.1% for the base oil consisting of the silicone curved fluid and the dried stellate fluid, respectively.
~3.0% by weight.

(2) Ashless dispersant: Next, an ashless dispersant, for example, an ashless dispersant containing succinimide and/or its derivatives as a main component, can be blended into the hydraulic actuation of the present invention. These are used to prevent the agglomeration and precipitation of the base oil particles of the phosphoric acid compound, and to avoid developing long-term stable friction detection properties and anti-wear properties. The ashless dispersant shown in Noshiro below must be used.

The above-mentioned ashless dispersant containing succinimide and/or its derivatives as a main component is 0.05 to 0.05% of the base oil from the viewpoint of effectiveness.
1 width hanging% is used.

(3) Metal deactivator: In the hydraulic oil composition of the present invention, a 1lsb bridge made of a composite phase of Plasdeck, copper, lead, etc. (when used in a manner that comes into contact with a metal) In order to prevent the copper and buttons in the composite material from eluting into the base oil, it is effective to include a metal deactivator.

When copper, lead, zinc, etc. in the composite +Δ are eluted into the base oil,
Not only does it degrade the base oil, but it also weakens the complex. As this type of metal deactivator component, thiadiazole type, triazole type, etc. shown in the following Noshiro may be blended in an amount of 0.01 to 0.5% by weight based on the base oil.

Kuthiadiazole series> -N R-8-8-CG-8-8-R \/ (R=C+ ~11- or 1so-alkyl group of Cog] <1~Riasol series> to 1: I?=C , ~C12 old or 1so-argyl group] (4) Others: In the hydraulic oil composition of the present invention, in addition to the above-mentioned components, detergents and dispersants widely used in the art can be used. Needless to say.

Examples of this type of detergent dispersant include metal sulfonates, metal phosphones 1 to 1, and metal phenes 1 to 1 (metal components include (Hg, Ca, Ba, Na, etc.).

In addition, if necessary, for example, 4,4-methylbis-? , 6-di-t-butylphenol, phenyl-α-nanothylamine, and the like are used. this is,
0.0 for base oil! 'i to 10% by weight may be blended.

(Examples) Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

<Example]~2/Comparative Examples 1~2> The automotive hydraulic fluid of the present invention and the hydraulic fluid for comparison were prepared using the base oil components shown in Table 1 below and the additive 7J [I component]. Prepared.

Next, various evaluation items shown in Table 1 were tested.

The results are shown in Table 1.

As shown in Table 1, the examples have viscosity-temperature characteristics ranging from the low-temperature side to the high-temperature side (Q resistance, flammability,
It can be seen that it is comprehensively superior in properties such as evaporation loss and shear stability (viscosity reduction rate).

(Left below) (Effects of the invention) The automotive hydraulic fluid based on the silicone-based hydraulic fluid and ester-based hydraulic fluid of the present invention has excellent viscosity-temperature characteristics at high and low temperatures. Flammability, evaporation loss, seizure resistance, shear stability (viscosity reduction rate)
It also has excellent properties such as:

Therefore, the automotive hydraulic fluid of the present invention can be used as a hydraulic fluid for a bending device that controls the posture of a vehicle, etc.
Excellent hydraulic response can be achieved over a long period of time.

Patent applicant: Toa Renki Kogyo Co., Ltd.

Claims (1)

[Claims] A hydraulic fluid for automobiles with excellent hydraulic response, characterized by being composed of a silicone-based hydraulic fluid and an ester-based hydraulic fluid.