JPH04363639A - Lubricant tester for automatic transmission - Google Patents

Abstract

PURPOSE:To achieve the testing of deterioration in thermal oxidation and in friction of a lubricant (ATF) for an automatic transmission simultaneously with the passage of time and quick and accurate evaluation of low speed slip performance of the ATF and sustainability (endurance) of the low speed slip performance, especially helpful for the development of the ATF with excellent shudder resistance life. CONSTITUTION:This tester has a transmission clutch testing means 2 to measure various mu characteristics such as dynamic friction coefficient (mud) and static friction coefficient (mus) and an ATF thermal oxidation deterioration testing means 3 which is kept at a specified temperature to test deterioration in thermal oxidation of an ATF. The transmission clutch testing means 2 has a transmission clutch testing tank 4 to be loaded with the ATF and a clutch disc 5 as rotary metal body and a clutch plate 6 with a friction material which is pressed onto the clutch disc 5 by a specified pressing force with a piston are arranged in the tank 4. The clutch disc 5 is driven to rotate at a specified rotational speed with a motor M1 for testing traction or a motor M2 for testing engagement by switching clutches 8 and 12. The ATF is circulated between the transmission clutch testing means 2 and the ATF thermal oxidation deterioration testing means 3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides lubricating oil for automatic transmissions (
From now on, “ATF: Automatic Transmission
sion Fluid”. ), and in particular, A
It is possible to simultaneously test TF deterioration and ATF thermal oxidative deterioration. Therefore, it is possible to measure changes over time in the ATF friction coefficient (μ) characteristics due to deterioration, and to evaluate the performance life of the ATF, especially the shudder resistance performance in the lock-up clutch section. The present invention relates to an ATF test device that can easily evaluate the lifespan.

0002

[Background Art] In recent years, automatic transmissions (torque converters) have come to be used in many automobiles in Japan, and in particular, automatic transmissions with lock-up clutches, which are effective in improving fuel efficiency, are frequently used. . Although automatic transmissions with lock-up clutches can be expected to save fuel, abnormal vibrations accompanied by noise called shudder may occur due to stick-slip when the lock-up is activated. Such a stick-slip phenomenon is likely to occur particularly in a low speed range. Therefore, the occurrence of shudder is one of the important problems that must be solved in the so-called "automatic transmission with slip control lockup" that operates the lockup clutch while slipping even in the low speed range.

[0003] In order to prevent such stick-slip phenomenon and avoid the occurrence of shudder, a material with excellent low-speed sliding performance, that is, the coefficient of friction increases as the sliding speed increases, and a material with excellent low-speed sliding performance is required. It is essential to use ATF with excellent sustainability (durability). In general, the deterioration mechanisms of ATF used in automatic transmissions include thermal oxidative deterioration that occurs at a maximum temperature of about 150°C inside the automatic transmission, and friction that occurs in the clutch (friction surface temperature of 200°C to 200°C).
300℃).

On the other hand, currently, as a test device for evaluating the performance of ATF, (1) during ATF, the friction material of the clutch part is pressed against a mating metal surface that is in relative rotational motion, and the friction force is measured; coefficient (μd), static friction coefficient (μs
) to measure various μ characteristics such as SAE No. 2 Friction tester or sliding friction tester (LVFA: Low Velo
City Friction Apparatus)
(2) After immersing the catalyst in ATF and stirring the sample with a stirring rod at a specified temperature for a specified period of time to oxidize it, measure the kinematic viscosity and total acid value of the oxidized oil and compare it with the unoxidized oil. ,
TOST (Turbine oil oxidation)
n Stability Test), ISOT (In
diana Stirring Oxidation
Test ) or ABOT (AluminumBeak
erOxidation Test) There is an oxidation stability tester.

[0005]

[Problem to be solved by the invention] However, the above (
SAE No. described in 1). 2 Friction testing machines etc.
Although it is possible to evaluate the performance of an ATF by testing the frictional deterioration of the ATF, it is not possible to test and evaluate thermal oxidative deterioration. Furthermore, the tester described in (2) above was originally used to test the oxidation stability of turbine oil or lubricating oil for internal combustion engines, and was used to evaluate the thermal oxidative deterioration of ATF. Although it can be adopted as one test method,
It is not possible to evaluate the frictional deterioration of TF.

As mentioned above, the deterioration mechanisms of ATF used in automatic transmissions include thermal oxidation deterioration and frictional deterioration, and it is only by measuring these two types of deterioration simultaneously over time that the low-speed slipping performance of ATF can be determined. and evaluation regarding the sustainability (durability) of low-speed sliding performance. In this respect, no conventional test equipment is satisfactory.

Therefore, an object of the present invention is to be able to simultaneously test thermal oxidative deterioration and frictional deterioration of ATF over time;
An object of the present invention is to provide a testing device for lubricating oil for automatic transmissions that can quickly and accurately evaluate the low-speed slipping performance of ATF and the sustainability (durability) of the low-speed slipping performance.

[0008]

[Means for Solving the Problems] The above objects are achieved by a lubricating oil testing device for automatic transmissions according to the present invention. In summary, the present invention provides a transmission clutch testing means for conducting a clutch engagement durability test and a clutch dragging durability test to measure the coefficient of friction (μ) characteristics of a lubricating oil for an automatic transmission, and It is characterized by having a thermal oxidative deterioration test means for testing oxidative deterioration, and a means for circulating the automatic transmission lubricating oil subjected to the test between the speed change clutch testing means and the thermal oxidative deterioration testing means. This is a lubricant testing device for automatic transmissions.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lubricating oil testing apparatus for automatic transmissions according to the present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a lubricating oil for automatic transmissions according to the present invention (
An example of an ATF test device is shown. In this embodiment, the ATF testing device 1 includes a speed change clutch testing means 2 that measures various μ characteristics such as a dynamic friction coefficient and a static friction coefficient;
ATF thermal oxidative deterioration test means 3 for testing thermal oxidative deterioration of ATF.

The speed change clutch testing means 2 is a conventional SAE
No. It has the same configuration as the friction tester 2 and is equipped with a variable speed clutch test tank 4 filled with ATF. A clutch plate 6 provided with a friction material that is pressed with a predetermined pressing force is arranged at a position (not shown). A rotational drive shaft 7 attached to the clutch disc 5 is connected to a drag test motor M1 via a clutch 8, a torsion bar 9, and a reduction gear 10. In addition, an engagement test motor M2 is connected to the drive shaft 7 via a reducer 11, a flywheel 13, and a clutch 12.
are concatenated. Therefore, the clutch disk 5 is rotated at a predetermined rotational speed by the drag test motor M1 or the engagement test motor M2 by switching the clutches 8 and 12. On the other hand, clutch plate 6
is connected to a torque meter 14, and continuously measures the torque applied to the clutch plate 6. Also, clutch test tank 4
The ATF inside is maintained at, for example, 100° C., which corresponds to the temperature of the clutch portion of an actual automatic transmission.

As understood from the above description, according to the present invention, the speed change clutch testing means 2 performs a clutch engagement durability test (Dd) and a clutch drag durability test (Sd).
) is carried out. Clutch engagement durability test (Dd)
The clutch 12 is turned on, the clutch 8 is turned off, the engagement test motor M2 is driven, and the clutch disk 5 is rotated at a constant speed, for example, but not limited to, 3600 rpm. Further, the clutch plate 6 is pressed against the clutch disk 5 in a predetermined engagement pattern (predetermined surface pressure and time) by controlling the piston. To give an example of an engagement pattern, the clutch plate 6 is
The engagement cycle is such that the clutch disc 5 is pressed for 15 seconds with a surface pressure of 10 kgf/cm2, then released for 15 seconds, pressed again for 15 seconds with a surface pressure of 10 kgf/cm2, and then released for 15 seconds. It is repeated a predetermined number of times.

[0013] Clutch drag durability test (Sd)
The clutch 8 is turned ON and the clutch 12 is turned OFF, the drag test motor M1 is driven, and the clutch disk 5 is rotated at a constant speed, usually, but not limited to, 50 rpm. Further, the clutch plate 6 is pressed against the clutch disk 5 in a predetermined engagement pattern (predetermined surface pressure and time) by controlling the piston. At this time, if a stick-slip phenomenon occurs between the clutch disk 5 and the clutch plate 6, a force that changes in a wave-like manner over time is recorded on the torque meter due to the action of the torsion bar. To give an example of an engagement pattern, the clutch plate 6 is pressed against the clutch disc 5 for 25 seconds with a surface pressure of 3 kgf/cm2, then the pressure is released for 5 seconds, and then pressed again for 25 seconds with a surface pressure of 3 kgf/cm2. The engagement cycle is repeated a predetermined number of times, such as being opened for 5 seconds and then released for 5 seconds.

[0014] The engagement pattern in the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) is not limited to the above example, but may be applied to an automatic transmission with lockup in which ATF is actually used. Various changes can be made depending on the situation.

The ATF thermal oxidative deterioration test means 3 includes a sample container 21 and an oil bath 2 that heats the sample container 21 to a predetermined temperature.
2, and heater means 23 for heating the oil bath 22. A breather 24 is provided in the sample container 21 to vent air from inside the sample container 21. The oil bath 22 is preferably made of silicone oil, which is less likely to change over time due to thermal oxidative deterioration. The ATF in the sample container 21 is at the temperature inside the torque converter of an actual automatic transmission, for example 150°C.
will be maintained. Further, in the sample container 21, steel, copper, or the like is placed as a catalyst, as is usually used in the oxidation stability test of lubricating oil.

The speed change clutch test tank 4 and sample container 21
is connected to the sample container 21 through a connecting pipe 32, and the ATF in the speed change clutch test tank 4 is flowed into the sample container 21 through the connecting pipe 32. Further, the ATF in the sample container 21 is returned to the variable speed clutch test tank 4 through a connecting pipe 32 equipped with an oil cooler 31 and an oil pump P. As described above, according to the present invention, the ATF operates between the speed change clutch testing means 2 and the A by means of the circulation means constituted by the connecting pipe 32, the oil pump P, etc.
It is circulated between the TF thermal oxidative deterioration test means 3. The oil cooler 31 has a rating of 150 in the ATF thermal oxidation deterioration test means 3.
This is for cooling the ATF that has risen to 100°C to 100°C and circulating it to the variable speed clutch testing means 2.

FIG. 2 shows a test method using the automatic transmission lubricating oil testing device 1 according to the present invention. Figure 2(A)
According to the test method according to the test pattern shown in
Initial characteristics of the ATF to be tested, such as the coefficient of friction during stick-slip (μss) and the coefficient of friction during drag (μs) at low speed rotation, which indicates anti-shudder performance.
, the friction coefficient during clutch engagement, which indicates clutch engagement performance (
μd) and the friction coefficient (μ0) at maximum torque just before the clutch plate stops are measured. Such measurement of the friction coefficient μ has been conventionally performed using, for example, SAE No. 2 in a friction tester, in a manner well known to those skilled in the art.

The ATF whose initial μ characteristics were measured is filled in a predetermined amount into the variable speed clutch testing tank 4, and is circulated between the variable speed clutch testing means 2 and the ATF thermal oxidative deterioration testing means 3 by the lubricating oil pump P. Ru. The amount of ATF subjected to the test is the minimum required amount, for example, in the variable speed clutch test tank 4.
If the capacity is 0.8 liters, the amount of sample oil will be about 2 liters, and the circulation rate will be 10 ml/min.

The speed change clutch test means 2 performs a clutch engagement durability test (Dd) and a clutch drag durability test (Sd).
) is carried out. According to the test pattern of the embodiment shown in FIG. 2(A), the clutches 8 and 12 are turned on alternately,
Therefore, the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) are conducted alternately. In each test, the torque value output from the torque meter 14 and the driving rotational speed of the drive motors M1 and M2 are continuously measured by a tachometer (not shown).

When measuring the drag friction coefficient (μs), the torsion bar 9 shown in FIG. 1 is replaced with a highly rigid straight bar.

If the above-mentioned clutch engagement pattern is adopted for this clutch engagement durability test (Dd) and clutch drag durability test (Sd), the clutch plate 6 will hold the clutch disc 5 for 15 seconds at a surface pressure of 10 kgf/cm2.
The clutch plate 6 is pressed against the clutch disc 5 for 25 seconds at a surface pressure of 3 Kgf/cm2, and then the pressure is released for 15 seconds to perform a clutch engagement durability test (Dd). After the pressure is released for a second, a clutch drag durability test (Sd) is performed. Next, a clutch engagement durability test (Dd) and a clutch drag durability test (S) were performed using the same clutch engagement pattern.
d) is repeated. As described above, in this embodiment, the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) are performed in a one-minute cycle. Normally, the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) can be performed for any number of n cycles, and the durability test is performed by repeating cycles corresponding to the actual mileage of the automobile.

After such a durability test, the μ characteristics of the ATF, ie, the friction coefficients (μss), (μs), (μd) and (μ0) are measured. Next, in the same manner as described above, the speed change clutch testing means 2 performs a clutch engagement durability test (Dd) and a clutch drag durability test (Sd).
) is performed for a predetermined n cycles, and then the μ characteristic of the ATF is measured.

Using this test pattern, a clutch engagement durability test (Dd) and a clutch dragging durability test (Sd) were conducted.
) is repeated until the total number of cycles corresponds to, for example, a mileage of a car of 200,000 km.

When the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) in the variable speed clutch testing means 2 are completed in this way, the clutch plate 6
Replace the friction material with a new one, measure the μ characteristics of the ATF, and confirm the μ characteristics of the ATF after the durability test.

[0025] Clutch engagement durability test (Dd) and clutch dragging durability test (Dd) using the above-mentioned speed change clutch testing means 2.
While Sd) continues to be carried out, the ATF thermal oxidation deterioration test means 3 simultaneously forcibly carries out thermal oxidation of the ATF. Therefore, in the test carried out in the present invention, it is possible to accurately evaluate the change over time in the μ characteristic of the ATF due to deterioration.

According to the test method according to the test pattern shown in FIG. 2(B), first, the initial μ of the ATF to be tested is
A property is measured. Similar to the test method shown in FIG. 2(A), the ATF for which each initial μ characteristic was measured is filled in a predetermined amount into the variable speed clutch test tank 4, and the oil pump P is used to transfer the ATF to the variable speed clutch testing means 2 and cause thermal oxidative deterioration of the ATF. It is circulated between the test means 3 and the test means 3.

In the variable speed clutch testing means 2, a clutch engagement durability test (Dd) is first performed on, for example, the clutch plate 6.
A clutch engagement pattern is adopted in which the clutch is pressed against the clutch disc 5 for 15 seconds with a surface pressure of 10 kgf/cm2, and then the pressure is released for 15 seconds, and the clutch is carried out for an arbitrary number of n cycles, which corresponds to the actual mileage of the car. Durability tests were conducted by repeating this cycle.

Next, a clutch drag durability test (Sd
) is carried out. If the above clutch engagement pattern is adopted, the clutch plate 6 will have a surface pressure of 3 kgf/cm2.
The clutch disk 5 is pressed against the clutch disk 5 for 25 seconds, and then the pressure is released for 5 seconds, and an arbitrary number of n cycles are performed, and the durability test is performed by repeating cycles corresponding to the actual mileage of the automobile.

After such a durability test, the μ characteristics of ATF, namely, the friction coefficient (μss), (μs), (μd
) and (μ0) are measured. Next, in the same manner as described above, the variable speed clutch testing means 2 performs a clutch engagement durability test (Dd) and a clutch drag durability test (S).
d) is performed, and then the μ characteristics of the ATF are measured. Such a test pattern is used until the total number of cycles of the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) reaches a cycle equivalent to, for example, a mileage of 200,000 km of an automobile.

When the clutch engagement durability test (Dd) and the clutch drag durability test (Sd) in the variable speed clutch testing means 2 are completed in this way, the clutch plate 6
The friction material of A was replaced with a new one and the μ characteristics of the ATF were measured.
Check the μ characteristics after the TF durability test.

Clutch engagement durability test (Dd) and clutch dragging durability test (Dd) using the above-mentioned speed change clutch test means 2
While Sd) continues to be carried out, the ATF thermal oxidation deterioration test means 3 simultaneously forcibly carries out thermal oxidation of the ATF. Therefore, in the test carried out in the present invention, it is possible to accurately evaluate the change over time in the μ characteristic of the ATF due to deterioration.

According to the test device according to the present invention, regardless of which of the above test patterns is adopted, the friction coefficient (μ) characteristics of the ATF that are correlated with the automatic transmission installed in an actual automobile can be obtained; The low-speed slipping performance of the ATF and the sustainability (durability) of the low-speed slipping performance can be quickly and accurately evaluated, and the lifespan of the shudder resistance of the ATF can be comprehensively determined. FIG. 3 shows another embodiment of the ATF testing device of the present invention. According to this embodiment, the speed change clutch testing means 2 and the thermal oxidation deterioration testing means 3 are provided side by side, that is, configured as one unit.

In other words, according to this embodiment, the speed change clutch testing means 2, as in the previous embodiment shown in FIG.
A speed change clutch test tank 4 filled with ATF is provided, and a clutch disk 5 and a clutch plate 6 are arranged in the tank 4. Further, the clutch disc 5 is connected to the clutches 8 and 1.
By switching 2, the drag test motor M1
Alternatively, it is rotated at a predetermined rotational speed by an engagement test motor M2. On the other hand, the clutch plate 6 is connected to a torque meter 14 to continuously measure the torque applied to the clutch plate 6. In addition, although details will be explained later, in order to circulate the ATF in the speed change clutch test tank 4,
A propeller P is provided on a rotary drive shaft 7 connected to the clutch disc 5.

Furthermore, according to this embodiment, the speed change clutch test tank 4 is made larger than the test tank 4 in the embodiment shown in FIG.
A thermal oxidative deterioration test means 3 is disposed adjacent to one end of the clutch plate 6. The ATF in the test tank 4 is stored in the variable speed clutch test tank 4 portion constituting the thermal oxidative deterioration test means 3.
Heater means 23 is arranged to maintain the temperature at, for example, 150°C. In addition, plate-shaped or coil-shaped steel, copper, or the like is placed as a catalyst in the variable speed clutch test tank 4 that constitutes the thermal oxidative deterioration test means 3, as is normally used in the oxidation stability test of lubricating oil. It will be done. In some cases, it is also possible to add soluble metals. Furthermore, test tank 4
By forming itself from such a metal, the addition of a catalyst can also be omitted. Also, variable speed clutch test tank 4
A breather 24 is provided to vent air from inside the test chamber 4.

[0035] With this configuration, the speed change clutch test tank 4 is filled with ATF. The ATF in the tank is supplied to the clutch disk 5 and the clutch plate 6 by a circulation means rotated by the drive shaft 7, that is, a propeller P, and then passed through a through hole 6a formed in the end plate of the clutch plate 6. It is sent to the thermal oxidative deterioration test means 3.

ATF flowing into the thermal oxidative deterioration test means 3
undergoes thermal oxidation and is returned to the transmission clutch testing means 2 again. Preferably, in order to promote the flow of ATF, a rectifying plate 33 is preferably disposed in the portion of the variable speed clutch test chamber 4 where the thermal oxidative deterioration test means 3 is disposed.

As described above, according to this embodiment, ATF is circulated between the speed change clutch testing means 2 and the ATF thermal oxidation deterioration testing means 3 by the circulation means constituted by the propeller P or the like.

In this embodiment, the ATF can also be tested using the same test pattern as described above, and the same effects can be achieved.

[0039]

Effects of the Invention The automatic transmission lubricating oil testing device according to the present invention configured as described above can simultaneously test thermal oxidative deterioration and frictional deterioration of ATF over time, and improve low-speed slipping performance of ATF. It is possible to quickly and accurately evaluate the sustainability (durability) of low-speed sliding performance and is particularly useful for developing ATFs with excellent shudder resistance and long life.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of a lubricating oil testing device for an automatic transmission according to the present invention.

FIG. 2 is a flowchart showing a test method using the automatic transmission lubricant test device according to the present invention.

FIG. 3 is a diagram showing the configuration of another embodiment of the automatic transmission lubricating oil testing device according to the present invention.

[Explanation of symbols]

1 Lubricating oil test device for automatic transmission 2
Variable clutch test means 3
Thermal oxidative deterioration test means 4 Variable clutch test tank 5 Clutch disc 6 Clutch plate 14 Torque meter 21 Sample container 22 Oil bath 23 Heater means P Circulation means

Claims (1)

[Claims] Claim 1: A transmission clutch test means for measuring the coefficient of friction (μ) characteristics of a lubricating oil for an automatic transmission by conducting a clutch engagement durability test and a clutch dragging durability test; An automatic transmission characterized by having a thermal oxidative deterioration test means for testing, and a means for circulating the automatic transmission lubricating oil subjected to the test between the speed change clutch testing means and the thermal oxidative deterioration testing means. Machine lubricant testing equipment.