JP2012017808A - Wet multiple disc clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a superior friction coefficient and a torque transmitting performance, and reduce weight and achieve high efficiency, by reducing the number of friction materials and separator plates without wearing the surface of the friction materials.SOLUTION: The wet multiple disc clutch transmits a rotation torque by engagement with the friction materials 4a in lubricating oil. The clutch is constituted by forming a plurality thin grooves 30 such that the groove area (surface groove ratio) of the thin grooves 30 to the friction area becomes 10 to 70% in the whole face of a part contacting with the friction materials 4a of the face engaging with at least the friction materials 4a.

Description

  The present invention is a wet multi-plate clutch that transmits torque by applying pressure between a wet friction material and a separator plate facing each other in a state immersed in oil. The present invention relates to a wet multi-plate clutch having a separator plate that can realize the above.

This type of wet multi-plate clutch is a friction provided with a plurality of or single friction plates used in automatic transmissions (hereinafter also simply referred to as “AT”) for automobiles, and transmissions for motorcycles. It is used for a material engaging device.
This wet multi-plate clutch is an organic fiber that is cut into segment pieces along a flat ring shape on a flat ring metal core in order to reduce costs by improving material yield and to reduce fuel consumption in vehicles by reducing drag torque. A friction material obtained by blending resin, a friction modifier (organic component, inorganic component), and the like, and thermosetting, and a plurality of steel plate separator plates are alternately stacked. This friction material is made up of a plurality of segment pieces, which are sequentially arranged with an adhesive with an interval between them as an oil groove, and are adhered around the entire surface. If necessary, the segment pieces are similarly adhered to the back surface as well. A segment type friction material has been developed.

  For example, wet multi-plate clutches are used in ATs for automobiles, etc., and a plurality of segment type friction materials and a plurality of separator plates made of steel are alternately stacked, and all separator plates are pressed by hydraulic pressure. Torque is transmitted. Lubricating oil (Automatic Transmission Fluid, Automatic Transmission Lubricating Oil, hereinafter referred to as “ATF”) is used between the two plates for the purpose of absorbing frictional heat generated when shifting from the non-fastened state to the fastened state and preventing wear of the friction material ("ATF" is a registered trademark of Idemitsu Kosan Co., Ltd., but does not directly mean the trademark here). Therefore, at the time of engagement, ATF is present at the friction interface, and the friction coefficient μ remains at about 0.16 at the maximum.

  In recent years, with the reduction in size and weight of ATs aimed at lower fuel consumption than in the past, ATs that use wet friction materials such as segment type friction materials have been reduced in weight by reducing the number of friction materials, and higher The need for efficiency is increasing, and for that purpose, it is necessary to further increase the friction coefficient μ. As a property related to friction, by providing a fine oil groove in the separator plate, which is the counterpart of the wet friction material, the heat generated during engagement is efficiently reduced by ATF, heat resistance is improved, and friction characteristics are improved. The following inventions are disclosed in Patent Document 1 and Patent Document 2 for the purpose of stabilization.

  Patent Document 1 is an invention of a separator plate used in a wet type multi-plate clutch, in which a minute unevenness extending regularly in a predetermined direction is provided on a friction surface, and a corner protruding from the other side of the unevenness is removed. A technique in which the tip is flattened is disclosed. Thus, the friction characteristics of the wet multi-plate clutch can be improved, the cooling effect can be enhanced, and wear of the wet friction material can be prevented.

  In Patent Document 2, a separator plate is formed by forming a circumferential groove on a frictional engagement surface that comes into contact with the friction plate, so that the frictional engagement surface between the separator plate and the friction plate is sufficient. An appropriate amount of lubricating oil can be supplied, the amount of heat generated by friction can be suppressed to prevent wear, and the wet friction material can be sufficiently cooled.

JP 2004- 211728 A JP 2005-308183 A

  However, in the technique of Patent Document 1, it is said that the friction characteristics can be stabilized over a long period of time. However, the ratio of the groove area to the friction area is extremely small, so that the amount of spreading of the lubricating oil is improved. Therefore, the coefficient of friction is not sufficiently improved.

  Further, in the technique of Patent Document 2, the concave portion is formed in the circumferential direction of the separator plate in order to suppress the heat generation amount due to wear. However, the thickness of the oil film present at the friction interface during engagement can be reduced. Only by friction material. And since the depth of the recess is formed deeper than the thickness of the friction material (generally about 0.5 mm), the uneven surface is too large and the friction surface of the wet friction material that is the counterpart material is likely to wear. The life of wet friction materials including segment type friction materials will be shortened. Furthermore, since the width of the recess for suppressing the amount of heat generated due to wear is too wide, the contact area with the wet friction material becomes small, and a good friction coefficient and torque transmission performance may not be obtained.

  Therefore, the present invention can provide an excellent coefficient of friction and torque transmission performance, does not wear the surface of the friction material, and can achieve weight reduction and high efficiency by reducing the number of friction materials and separator plates. An object is to provide a wet multi-plate clutch.

In the wet multi-plate clutch according to the first aspect of the present invention, there is provided a friction plate in which a friction material is bonded to both surfaces or one surface of a flat ring metal core, and the friction material of the friction plate and a separator plate in lubricating oil. In a wet multi-plate clutch that controls transmission of rotational torque by engaging or disengaging the engagement, a surface groove for a friction area of a portion of the separator plate that is in contact with the friction material and that is in contact with the friction material A plurality of fine grooves are formed so that the ratio, that is, the ratio of the groove area provided on the surface of the separator plate to the friction area is 10 to 70%.
Here, the friction area of the portion of the separator plate that is in contact with the friction material that is in contact with the friction material is the area of the friction material that faces the separator plate with respect to the opposing surface.
The friction plate is formed by adhering a friction material to both surfaces or one surface of a flat ring-shaped cored bar.

  The wet multi-plate clutch according to the invention of claim 2 has the friction coefficient μ of 0.16 to 0.20.

  In the separator plate of the wet multi-plate clutch according to the invention of claim 3, the width and depth of the plurality of narrow grooves are 10 to 500 μm.

  In the separator plate of the wet multi-plate clutch according to a fourth aspect of the invention, all of the plurality of fine grooves are provided in a lattice shape at equal intervals of 100 μm or more.

  The separator plate of the wet multi-plate clutch according to the invention of claim 5 is provided with the plurality of narrow grooves on both surfaces.

According to the first aspect of the present invention, the ratio of the plurality of fine grooves (oil grooves) formed in the separator plate to the friction area is 10 to 70%, so that the oil present at the friction interface when engaged with the friction material. Is smoothly discharged through the oil passage, so that the oil film thickness can be reduced, and thereby a high friction coefficient μ can be realized while maintaining the positive gradient μ-V characteristic.
For this reason, when a wet multi-plate clutch is configured using the separator plate of the present invention, it is possible to reduce the number of friction materials and separator plates required, and the wet multi-plate clutch can be reduced in weight and size. And high efficiency can be achieved.

  Since the friction coefficient μ of the invention of claim 2 is 0.16 to 0.20, in addition to the effect of the invention of claim 1, a high friction coefficient μ is maintained while maintaining a positive gradient μ-V characteristic. Can be realized.

  In the invention of claim 3, since the depth of the narrow groove is 10 to 500 μm, in addition to the effect of the invention of claim 1 or claim 2, the oil is smoothly discharged through the narrow groove, and the friction material Oil that is present at the friction interface during engagement with the separator plate is smoothly discharged through the oil passage, and the oil film thickness can be reduced.

  In addition to the effect of any one of the first to third aspects, the invention according to the fourth aspect provides a sufficient contact area with the friction material when the interval between the narrow grooves is 100 μm or more. High friction coefficient μ can be maintained.

  In addition to the effect of any one of claims 1 to 4, since a single type of separator plate can be applied to various types of friction materials if narrow grooves are provided on both sides of the separator plate as in the invention of claim 5. Thus, it is possible to manufacture without distinction between one in which only one surface of the friction plate is engaged with the separator plate and one in which both surfaces of the friction plate are engaged with the separator plate.

It is principal part sectional drawing which cut | disconnected the whole wet multi-plate clutch of Embodiment 1 of this invention in the shaft direction. It is a front view of the separator plate of the wet multi-plate clutch of Embodiment 1 of the present invention. It is a principal part enlarged front view of the separator plate for wet multi-plate clutches of Embodiment 2 of the present invention. It is a principal part enlarged front view of the separator plate for wet multi-plate clutches of Embodiment 3 of this invention. It is a characteristic view which shows the μ-V characteristic which is a friction coefficient according to the number of rotations at 40 ° C. of the wet multi-plate clutch according to Embodiment 1 of the present invention. It is a characteristic view which shows (micro | micron | mu) V characteristic which is a friction coefficient according to the rotation speed in 100 degreeC of the wet multi-plate clutch of Embodiment 1 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the same symbols and the same reference numerals mean the same or corresponding parts and functions, and therefore redundant description is omitted here.

[Overview]
An outline of the configuration of the wet multi-plate clutch according to the first embodiment of the present invention will be described.
FIG. 1 is a cross-sectional view showing a basic configuration of a wet multi-plate clutch 1 according to the first embodiment. The clutch case 2 that accommodates the clutch functional parts can freely move in the longitudinal direction of the shaft that transmits the power to the clutch case 2 and restricts the movement in the rotational direction, and the friction material 4a around the separator plate 3. The friction plate 4 is provided. The separator plate 3 is engaged with the spline groove 7 of the clutch case 2 by the spline 8 on the outer periphery thereof.

  The piston 5 presses the separator plate 3 toward the retaining ring 6 or releases the press. Specifically, by introducing hydraulic pressure into the oil chamber 11, the illustrated separator plate 3 is pressed to the right, and the friction plate 4 and the separator plate 3 are pinched. Further, when the pressure oil is reduced from the oil chamber 11, the piston 5 is returned to the left in the figure by the return spring 10 interposed between the piston retainer 9 and the piston 5.

  FIG. 2 is a front view of the separator plate 3, and the convex portion on the outer periphery shows the spline 8. A narrow groove 30 is provided in the friction surface 31 on both sides or one side to form a path for the ATF. The narrow groove 30 is formed with a width and depth of 10 to 500 μm. Desirably, some of the narrow grooves 30 are formed at linear positions connecting the inner periphery to the outer periphery of the separator plate 3.

  FIG. 3 is a front view of the separator plate 3 according to the second embodiment, which is another first case. The outer convex portion shows the spline 8. The friction surfaces 31 on both sides or one side are provided with narrow grooves 30 extending radially from the center thereof to form a path for the ATF. The narrow groove 30 is formed with a width and depth of 10 to 500 μm. The narrow groove 30 increases the density of the center of the friction surface 31.

FIG. 4 is a front view of the separator plate 3 of the third embodiment, which is another second case. The outer convex portion shows the spline 8. The frictional surfaces 31 on both sides or one side are provided with the lattice-like narrow grooves 30 to form a path for the ATF. The narrow groove 30 is formed with a width and depth of 10 to 500 μm. The separator plate 3 is a groove that communicates between the inner peripheral side and the outer peripheral side.
In addition, according to the experiments by the inventors, more and more patterns of the narrow grooves 30 were tested, but the results were not significantly different.

[Embodiment]
Next, the structure of the wet multi-plate clutch of each embodiment of the present invention will be described in detail.
As the friction material 4a of the friction plate 4 in the case of carrying out the present invention, a segment type friction material obtained by adhering a segment piece as a friction material base material to a ring-shaped double-sided surface or a single-side surface to a flat ring-shaped cored bar, a flat plate A ring-shaped friction material in which a ring-shaped friction material base material is bonded to both surfaces or one surface of a ring-shaped metal core, or both surfaces or one surface of a ring-shaped friction material are pressed or cut to form a plurality of oil grooves in the radial direction. Any known friction material such as a ring-type friction material may be used.

  Further, at least the surface of the friction plate 4 that engages with the friction material 4a is a separator plate that engages the friction material 4a on both surfaces, and a plurality of narrow grooves 30 are formed on both surfaces, but only one surface is the friction material. In the case of the separator plate that engages with 4a, it means that a plurality of fine grooves 30 may be formed only on one side, or a plurality of fine grooves 30 may be formed on both sides.

  The separator plate 3 is caused to function as a clutch by being opposed to and engaged with the friction material 4a and the separator plate 3. Even when only one surface is engaged with the friction material 4a, the provision of the plurality of narrow grooves 30 on both surfaces, that is, the surface that does not engage with the friction material 4a has no problem in use. Since both sides need not be manufactured separately from the separator plate 3 engaged with the friction material 4a, productivity is improved.

  Furthermore, at least the portion in contact with the friction material 4a means that the entire surface of the separator plate 3 is not normally in contact with the mating friction material 4a, but the friction material is provided on the outer peripheral side and the inner peripheral side of the surface of the separator plate 3. Since there is a part which does not contact 4a, the part which contacts the friction material 4a except the part is pointed out. When practicing the present invention, a plurality of narrow grooves 30 may be formed at least in a portion that contacts the friction material 4a, a surface including the inner peripheral side that does not contact the friction material 4a, or a friction material. This means that a plurality of fine grooves 30 may be formed on the surface including the outer peripheral side not in contact with 4a, and on the entire surface including the inner peripheral side and the outer peripheral side not in contact with the friction material 4a.

  Further, even if a plurality of narrow grooves 30 are formed on the entire surface including a portion not in contact with the friction material 4a, there is no problem in use, and the plurality of narrow grooves 30 are formed over the entire surface. In general, the processing is easier and the productivity is improved.

  Furthermore, in the case of carrying out the present invention, as a method of forming the plurality of narrow grooves 30, there are methods such as photo-etching, pressure pressing, cutting, electric discharge machining, laser processing, etc. The step of forming can be performed both before and after punching of the separator plate 3. The fine grooves 30 are formed by photo-etching by exposing a fine grid pattern created by CAD or the like on the surface of the separator plate 3 coated with a photosensitive resist film that is not attacked by an etching solution. The resist film of the other part is removed leaving the hit part. By immersing this in an etching solution, the portion from which the resist film has been removed is eroded and has fine fine grooves 30. At this time, the shape, width, and depth of the target groove can be adjusted by adjusting the etching depth by considering the shape, width, and time of immersion in the etching solution.

  When practicing the present invention, the groove area (surface groove ratio) of the narrow groove 30 with respect to the friction area of the separator plate 3 needs to be 10 to 70%, and if within that range, the friction material 4a and the separator The oil existing between the plates 3 can be quickly discharged. As a result, the thickness of the oil layer between the friction material 4a and the separator plate 3 can be reduced, and the friction coefficient is improved. Preferably, it is 30 to 70%, and in this range, when the rotational speed exceeds 20 rpm, the friction coefficient exceeds 0.18, more preferably 50 to 70%, and in this range, when the rotational speed exceeds 20 rpm. Further, the friction coefficient is improved to about 0.19 or more than 0.19.

  In carrying out the present invention, the narrow grooves 30 formed in the separator plate 3 may be formed in a lattice shape, and only in the radial direction or only in the circumferential direction, and further in a direction oblique to the radial direction. It may be formed. Preferably, the separator plate 3 is continuous from the inner peripheral side to the outer peripheral side, and ATF is supplied and discharged from both sides, so that the state of the friction interface can be made more ideal.

The width and depth of the narrow groove 30 are each preferably 10 to 500 μm. If the width and depth are within this range, the oil present at the friction interface passes through the narrow groove 30 that is an oil passage and is smoothly discharged and supplied. The required amount of oil can be present at the friction interface.
More preferably, the width of the narrow groove 30 formed in the separator plate 3 is 15 to 150 μm, and the depth of the narrow groove 30 is 15 to 50 μm. The interval between the narrow grooves 30 is required to be 100 μm or more and provided at equal intervals, and by setting this range, the area of the flat portion other than the narrow grooves 30 on the surface of the separator plate 3 is sufficiently large with the friction material 4a. It can be provided to such an extent that it can contact the

[Example]
Hereinafter, embodiments of the present invention will be described based on examples.
The separator plates used in Examples 1 to 4 according to the present invention were produced as follows.
A separator plate 3 made of a flat ring-shaped steel plate was prepared, a photoresist film was formed on both sides thereof, and then a fine lattice pattern mask prepared by CAD was coated on the photoresist film. Next, light was irradiated onto the both surfaces from the pattern mask to cure the portion irradiated with light, and then the photoresist film in the portion not irradiated with light was removed. By immersing this in an etching solution, the portion of the steel plate from which the resist film was removed was eroded to form the narrow groove 30. As a result, a pattern composed of fine lattice-shaped fine grooves 30 was formed on both surfaces of the separator plate 3.
Through this step, separator plates 3 of Examples 1 to 4 having the structure shown in Table 1 were obtained. In addition, the separator plate used for the comparative example 1 which is not based on this invention is a flat plate in which the conventional groove | channel is not formed.

With respect to the separator plates 3 of Examples 1 to 4 and Comparative Example 1, [oil spreading characteristics], [μ, μ-V characteristics] and [counterpart material aggression (standard load durability)] were measured.
[Test method for oil spread characteristics]

  5 μl (microliter) of ATF (registered trademark) was dropped on the surface of the separator plate 3, and the degree of oil spreading after 120 seconds at room temperature was determined based on the area after spreading in Comparative Example 1. In the separator plate 3 of Examples 1 to 4, it was measured how many times the reference area the oil spread was.

[Μ, μ-V characteristic test method]

Tester SAE # 2 was used as a test device, the disk (wet friction material) had 6 friction surfaces, the friction material 4a was a segment type friction material, the number of segment pieces was 40 on one side, the groove width was 2 mm, A segment piece having an outer diameter of 130 mm, an inner diameter of 107 mm, and a thickness of 2 mm was used.
Further, ATF (registered trademark) is used as the lubricating oil, the lubricating oil amount is 1000 ml / min, the oil temperature is 40 ° C. and 100 ° C., and the frictional rotational speed is 0.72, 2, 5, 10, 25, 50, The number of revolutions at 75 and 100 rpm, the surface pressure was 0.8 MPa, and the inertia was 0.343 kg · m 2.

[Counterpart material aggression (standard load durability) test method]

The tester uses a tester SAE # 2, the number of discs (wet friction material) is 3 and the friction surface is 6 (4 separator plates), and the friction material 4a is the number of segment pieces of segment type friction material. A 40-sided sheet having a groove width of 2 mm and a segment piece (friction material base material) having an outer diameter of 130 mm, an inner diameter of 107 mm, and a thickness of 2 mm was used.
In addition, ATF (registered trademark) is used as the lubricating oil, the amount of lubricating oil is 1000 ml / min, the oil temperature is 100 ° C., the friction rotational speed is 3600 rpm, the surface pressure is 0.8 MPa, the inertia is 0.343 kg · m ² , and the load For 5000 cycles.

Test results [oil spreading characteristics test and mating material aggression (standard load durability) test]

  5 μl (microliter) of ATF (registered trademark) was dropped on the surface of the separator plate 3, and the degree of oil spreading after 120 seconds at room temperature was based on the area after the expansion in Comparative Example 1 as “1”. In the separator plate 3 of Examples 1 to 4, if the area where the oil spreads is in the range of 1.3 to 2 times the standard, a high friction coefficient μ can be obtained as will be described later. confirmed.

Test results [μ, μ-V characteristics test]
As shown in the characteristic diagrams of FIGS. 5 and 6, according to the μ and μ-V characteristics data, the μ-V characteristics at 40 ° C. and 100 ° C. are common to the embodiments of the present invention. All the separator plates 3 of Examples 1 to 4 were compared with a value slightly less than 0.16 or 0.16, which is a friction coefficient μ of the separator plate of Comparative Example 1 that is not based on the present invention. A coefficient of friction of about 17 to 0.2 is shown, and the μ-V characteristic shows a positive gradient.

  In particular, when the surface groove ratio of the narrow groove 30 is in the range of 30 to 70%, the friction coefficient exceeds 0.18 in the range where the rotational speed exceeds 20 rpm, and in the range where the rotational speed exceeds 20 rpm in the range of 50 to 70%. Is improved to a level exceeding 0.19 or 0.19.

  According to the above three types of tests, Examples 1 to 4 based on the embodiment of the present invention are compared with Comparative Example 1 in which the surface groove ratio without the fine grooves 30 on the surface is 0 (zero). Since the separator plate 3 had a predetermined surface groove ratio, the amount of oil spread increased. This means that the oil easily diffuses on the surface due to the oil permeating into the fine grooves 30 on the surface.

As the oil spreads as described above, the oil layer between the friction material 4a and the separator plate 3 becomes thin as a result, so that the friction coefficient μ of the separator plate 3 with respect to the friction material 4a increases.
On the other hand, although it is considered that the wear amount of the friction material 4a is increased by increasing the friction coefficient μ, the wear amount is comparable to that of the separator plate of Comparative Example 1 that is not actually based on the present invention, that is, It shows the property that it stays at the same level as the counterpart material attack (standard load durability).
Summing up these three types of test results, according to the embodiment of the present invention, a separator plate having a high coefficient of friction, good attack on the mating material, and a positive gradient property in the μ-V characteristic is obtained. be able to.

  The friction plate 4 having the friction material 4a bonded in a ring shape on both or one side of the ring-shaped cored bar of the above-described embodiment is engaged with or engaged with the ring-shaped separator plate 3 in lubricating oil. The wet multi-plate clutch 1 that controls the transmission of rotational torque by releasing the engagement is configured such that the ratio of the plurality of narrow grooves 30 formed in the separator plate 3 to the friction area is 10 to 70%. The oil present at the frictional interface when engaged with 4a is smoothly discharged through the narrow groove 30 using the narrow groove 30 as an oil passage, so that the oil film thickness can be reduced, whereby a positive gradient μ A high friction coefficient μ can be realized while maintaining −V characteristics. When the wet multi-plate clutch is configured using the separator plate 3, it is possible to reduce the number of necessary friction materials 4a and the separator plate 3, and the wet multi-plate clutch 1 can be reduced in weight and size. High efficiency can be achieved.

In addition, since the wet multi-plate clutch 1 of the above embodiment has a friction coefficient μ of 0.16 to 0.20, it can maintain a positive gradient μ-V characteristic and realize a high friction coefficient μ. .
And when the depth of the narrow groove 30 is 10 to 500 μm, the oil passing through the narrow groove 30 is discharged more smoothly, and the oil present at the friction interface when the friction material 4 a and the separator plate 3 are engaged with each other. The oil is smoothly discharged through the narrow groove 30 serving as an oil passage, and the oil film thickness can be reduced.
Furthermore, when the interval between the narrow grooves 30 is 100 μm or more, a sufficient contact area with the friction material 4a can be obtained, and thus a high friction coefficient μ can be maintained.

  In addition, in the wet multi-plate clutch 1 of the above embodiment, if the narrow grooves 30 are provided on both surfaces of the separator plate 3, one type of separator plate 3 can be applied to the friction material 4a of various modes. Manufacture can be performed without distinction between one that engages with the separator plate 3 on one side and one that engages with the separator plate 3 on both sides of the friction plate 4.

1 wet multi-plate clutch 3 separator plate 4 friction plate 4a friction material 30 narrow groove

Claims (5)

A friction plate with a friction material bonded in a ring shape on both or one side of a ring shape of a flat ring metal core engages or disengages the ring-shaped separator plate in lubricating oil. In the wet multi-plate clutch that controls the transmission of
A surface with respect to a friction area engaged with the friction material on at least one ring-like surface or one surface of the separator plate that contacts the friction material on the opposing surface of the separator plate that engages with or releases the friction material. A separator plate, wherein a plurality of fine grooves are formed so that the groove ratio is 10 to 70%.   2. The separator plate according to claim 1, wherein a friction coefficient μ of the wet multi-plate clutch is 0.16 to 0.20.   The separator plate according to claim 1 or 2, wherein a width and a depth of the narrow groove of the wet multi-plate clutch are 10 to 500 µm.   The narrow grooves of the wet multi-plate clutch are all provided in a lattice shape at intervals of 100 μm or more and at equal intervals. Separator plate.   The separator plate according to any one of claims 1 to 4, wherein the narrow grooves of the wet multi-plate clutch are provided on both surfaces.

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