JP2005249106A - Wet multi-disk clutch for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet multi-disk clutch for an automatic transmission restricted in deformation thereof due to heat spots. <P>SOLUTION: The wet multi-disk clutch 10 for an automatic transmission has a friction plate 13 having a friction member 14 in a surface thereof and a separator plate 15 to be brought in slide-contact with a surface of the friction member 14 of the friction plate 13 to transmit rotating force. The separator plate 15 is formed by using an austenite group stainless steel containing Mn at 0.50 - 10 %, Ni at 3.0 - 27 % and Cr at 15 - 26 % by mass %. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wet multi-plate clutch used in an automatic transmission (automatic transmission) used in automobiles, agricultural machines, construction machines, and the like.

  Conventionally, in a wet multi-plate clutch in an automatic transmission, a friction plate is fixed to an engine torque input shaft, and a separator plate is fixed to a housing side.

  Here, since the separator plate is not a perfect plane but is slightly waved in the out-of-plane direction, local contact occurs when engaged with the friction plate. At this time, in the local contact portion of the separator plate, a temperature difference is generated between the contact side and the non-contact side, and the warpage of the separator plate is further increased. When the warpage of the local contact portion is increased, the waviness of the entire separator plate is increased, and a heat spot is generated in a false manner. In addition, when a heat spot occurs, the temperature instantaneously exceeds the ferrite / austenite transformation point near 700 ° C., so even if the temperature is lowered by subsequent cooling, deformation due to local transformation strain remains. Spot generation is promoted. As a result, there is a problem that the friction characteristics change due to the deformation of the separator plate due to the heat spot. In such a wet multi-plate clutch, a separator plate formed by punching a 0.2 to 0.32% C medium carbon alloy (for example, S20C equivalent steel, S35C, S35CM, etc.) by mass% is used. Was.

  As a countermeasure against the above problems, a differential device using a floating disk (floating plate) is known for the purpose of preventing the heat generated when a heat spot is generated in order to reduce the sliding speed that causes heat generation (for example, patents). Reference 1).

  In Patent Literature 1, the cone ring and the floating plate are disposed between the conical surface of each side gear and the conical surface of the differential case facing the conical surface, so that the sliding surface between the differential case and the side gear is Sliding on each sliding surface when either the cone ring, between the cone ring and the floating plate, between the floating plate and the side gear, or when the three opposing surfaces become sliding surfaces The wear resistance is improved by reducing the speed.

  Further, there is known a structure in which grooves are arranged on the front and back sides of the friction plate to cool by flowing oil (see, for example, Patent Documents 2 and 3).

  In Patent Document 2, the friction material fixed on the core plate is provided with an oil passage that penetrates from the inner peripheral surface to the outer peripheral surface of the friction material, and an oil groove that is open to the inner peripheral surface but not penetrated. By providing them alternately, oil distribution and storage are properly performed on the friction material, and the clutch disk cooling and separation in the case of clutch release are performed well, and the torque during operation is stabilized, The endurance life is also getting longer.

In Patent Document 3, an oil reservoir that communicates with the oil passage extending in the radial direction of the friction material is defined by a crest or trough of the outer peripheral spline of the rotating member and a trough or crest of the inner peripheral spline of the substrate. By circulating a large amount of oil through the oil passage, the sliding contact portion between the drive plate and the driven plate is cooled more effectively, and the sliding contact portion between the drive plate and the driven plate is effectively cooled. In addition to improving the durability by preventing clutch burn and deterioration of characteristics, it is also trying to improve clutch disengagement.
JP2003-049927A (page 3-4, FIG. 1) Japanese Patent Laid-Open No. 11-141570 (page 3, FIG. 3) JP 2002-372074 A (page 4-5, FIG. 1)

  However, in the above Patent Documents 1, 2, and 3, no fundamental countermeasure is taken from the material aspect, and it is difficult to eliminate deformation due to heat spots.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a wet-type multi-plate clutch for an automatic transmission in which deformation due to a heat spot is reduced.

The above object of the present invention is achieved by the following configurations.
(1) In a wet multi-plate clutch in an automatic transmission that includes a wet multi-plate clutch that contacts and separates a predetermined rotating element of the planetary gear unit and an input member,
The wet multi-plate clutch has a friction plate having a friction member on the surface, and a separator plate that slides on the surface of the friction member of the friction plate and transmits a rotational force,
The separator plate is formed of austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, and 15 to 26% Cr in mass%, and is wet in an automatic transmission. Plate clutch.

  (2) The wet multi-plate clutch in the automatic transmission according to (1), wherein the separator plate has a plurality of oil holes that allow oil to pass therethrough in a circumferential direction.

  According to the wet multi-plate clutch in the automatic transmission of the present invention, the separator plate is made of austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, 15 to 26% Cr in mass%. Due to the forming, the ferrite / austenite transformation that occurs in conventional steels is not performed. Therefore, the ferrite / austenite transformation at the time of heat spot generation is prevented and distortion due to the transformation can be reduced, so that the separator plate can be prevented from being deformed and the friction characteristics can be prevented from deteriorating.

  Moreover, according to the wet multi-plate clutch in the automatic transmission of the present invention, the separator plate has a plurality of oil holes in the circumferential direction through which oil passes, so that the clutch oil passes through the oil holes. Since the separator plate is cooled by this, the cooling effect can be enhanced.

  Hereinafter, a wet multi-plate clutch in an automatic transmission according to an embodiment of the present invention will be described in detail with reference to the drawings.

  1 is a sectional view of a wet multi-plate clutch in an automatic transmission according to an embodiment of the present invention, FIG. 2 is a front view of a separator plate used in the wet multi-plate clutch shown in FIG. 1, and FIG. 3 is a separator shown in FIG. The front view of the modification in a plate and FIG. 4 are the measurement data tables of an Example. The present invention aims to improve the durability by devising the material properties of the separator plate constituting the wet multi-plate clutch. Therefore, the structure shown in the drawings when carrying out the present invention is the same as that of a conventionally known wet multi-plate clutch. Therefore, the description of the specific structure of the wet multi-plate clutch is omitted.

  As shown in FIG. 1, a wet multi-plate clutch 10 in an automatic transmission according to an embodiment of the present invention includes a housing (corresponding to an input member) 11, an inner drum (corresponding to a rotating element) 12, and It is composed of a plurality of four friction plates 13 having friction materials 14 and 14 fixed on both surfaces, and a plurality of five separator plates 15.

  A housing (also referred to as an outer drum) 11 is formed in a cylindrical shape, and has a plurality of flanges (shown in FIG. 2) formed on the outer peripheral portion of the separator plate 15 in the circumferential direction of the inner peripheral surface. ) Eight concave grooves (not shown) of the same number as 16 are formed in the cylindrical direction. The housing 11 is integrally coupled to an output side gear (not shown). The housing 11 has a hydraulic mechanism (not shown) in which pistons (not shown) for pressing the plurality of separator plates 15 and the plurality of friction plates 13 in the cylinder direction are arranged in a cylinder (not shown). Built in the side.

  The inner drum 12 is formed in a cylindrical shape, and has the same number of concave grooves (not shown) as a plurality of flanges (not shown) formed on the inner peripheral portion of the friction plate 13 in the circumferential direction of the outer peripheral surface. Are formed in the cylinder direction. Since the inner drum 12 is coupled to a rotating element (clutch hub, input shaft) on the engine side, the rotation of the engine is input.

  The friction plate 13 is an annular plate member having an outer diameter smaller than the inner diameter of the housing 11, and a plurality of flange portions formed on the inner peripheral portion are recessed grooves of the inner drum 12. The spline is fitted by being inserted. Therefore, the friction plate 13 is locked in the rotational direction of the inner drum 12 and is coupled so as to be movable in the cylinder direction of the inner drum 12. Friction materials 14 and 14 are fixed to both surfaces of the friction plate 13.

  The separator plate 15 is a plate member formed in an annular shape, has an inner diameter larger than the outer diameter of the inner drum 12, and has a plurality of flanges 16 protruding from the outer peripheral portion of the main body 17. ing. The flange portion 16 is spline-fitted by being inserted into the recessed groove of the housing 11. Therefore, the separator plate 15 is locked in the rotation direction of the housing 11 and is coupled so as to be movable in the cylinder direction of the housing 11.

  The separator plate 15 is formed of austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, 15 to 26% Cr in mass%, and therefore, ferrite / austenite that occurs in conventional steels. Since no transformation is performed and ferrite / austenite transformation at the time of heat spot generation is prevented and distortion due to transformation can be reduced, deformation of the separator plate can be prevented, and deterioration of friction characteristics can be prevented.

  As shown in FIG. 2, the separator plate 15 has a plurality of flanges 16 protruding from the outer periphery. The collar portion 16 is formed in a quadrangular shape with a central portion cut into a semicircular shape. When the separator plate 15 is moved in the cylindrical direction of the housing 11 to perform the clutch operation because the eight flange portions 16 are spline-fitted into the concave groove of the housing 11, the separator plate 15 It operates reliably without causing sticking.

  Such a wet multi-plate clutch 10 is housed in a transmission case (not shown) filled with clutch oil, and the inner drum 12 is rotated by the power of the engine. At this time, each separator plate 15 and each friction plate 13 are in a non-contact state, and the rotational force of the inner drum 12 is not transmitted to the housing 11.

  Then, the hydraulic mechanism is activated to apply hydraulic pressure to the cylinder, and the piston plate presses the separator plate 15 at the left end in FIG. 1 in the cylinder direction to the right in FIG. Then, the separator plate 15 is brought into contact with the friction material 14 of the friction plate 13, and each separator plate 15 sandwiches the friction materials 14, 14 of each friction plate 13, and each separator plate 15, each friction plate 13, Are in close contact with each other. Thereby, the inner drum 12 is connected to the housing 11, and the output side gear is rotated by the power of the engine.

  On the other hand, in order to cut off the engine power, the hydraulic pressure is applied to the piston by the hydraulic mechanism and at the same time the hydraulic pressure is released. As a result, the piston is moved back and the separator plates 15 are separated from the friction materials 14 and 14 of the friction plates 13, and the rotational force of the inner drum 12 is not transmitted to the housing 11, so that the state is cut off.

  According to the wet multi-plate clutch 10 in the automatic transmission of this embodiment, the separator is made of austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, 15 to 26% Cr in mass%. Because the plate 15 is formed, the ferrite / austenite transformation that occurs in conventional steel is not performed. Therefore, ferrite / austenite transformation at the time of heat spot generation is prevented, and distortion due to transformation can be reduced. Therefore, deformation of the separator plate 15 can be prevented, and deterioration of friction characteristics can be prevented.

  Next, a modified example of the separator plate will be described with reference to FIG.

  As shown in FIG. 3, the separator plate 20 of the present modification is a plate member formed in an annular shape, and has a plurality of flanges 22 protruding from the outer peripheral portion of the main body 21. The flange portion 22 is spline-fitted by being inserted into a concave groove of the housing (see FIG. 1). A plurality of 32 oil holes (also called counterbore holes) 23 are formed in the separator plate 20 in the circumferential direction of the main body 21. Since the oil holes 23 are formed so as to penetrate from the front surface to the back surface of the main body 21, clutch oil (oil) passes from the front surface to the back surface or from the back surface to the front surface to cool the separator plate 20.

  The separator plate 20 is formed of 0.50 to 10% Mn, 3.0 to 27% Ni, and 15 to 26% Cr austenitic stainless steel in the same manner as the separator plate 15, The ferrite / austenite transformation that occurs in conventional steel is not performed, and ferrite / austenite transformation at the time of heat spot generation is prevented, and distortion due to transformation can be reduced, so that deformation of the separator plate is prevented, and friction characteristics are deteriorated. Can be prevented.

  According to this modification, since the separator plate 20 is provided with a plurality of oil holes 23 in the circumferential direction through which oil passes, the separator plate 20 is cooled by passing the clutch oil through the oil holes 23. Therefore, the cooling effect can be enhanced.

(Example)
Next, with reference to FIG. 4, the Example performed in order to confirm the effect of the wet multi-plate clutch in the automatic transmission which concerns on one Embodiment and modification of this invention is demonstrated.

In the examples, separator plates having five different compositions shown below were prepared.
Example 1: Austenitic stainless steel of 3.0% Ni, 15% Cr, 6.0% Mn in mass% Example 2: Austenitic system of 5.0% Ni, 18% Cr, 10% Mn in mass% Stainless steel Example 3: Austenitic stainless steel of 12% Ni, 17% Cr, 0.80% Mn by mass% Example 4: 26% Ni, 1.5% Cr, 0.10% Mn by mass% Austenitic stainless steel Example 5: 27% Ni, 22% Cr, 0.50% Mn austenitic stainless steel in mass% For comparison, a separator plate having the following composition was used as a comparative example.
Comparative Example 1: Alloy Steel with 0.75% Mn by Mass% Comparative Example 2: Alloy Steel with 0.50% Mn by Mass% (Experiment)
A test was conducted using a wet multi-plate clutch device comprising a clutch plate that slidably rubs against the separator plate and a ring gear of a planetary unit that slidably attaches the clutch plate in the axial direction.
Then, in the above-described wet multi-plate clutch device, the input shaft is rotated at 8000 rpm, and the separator plate and the friction plate are joined and separated at intervals of 10 seconds for a predetermined time, and then the amount of deformation of the separator plate is measured. The magnitude of deformation and damage due to heat spots were judged.
In the column of the deformation amount ratio in FIG. 4, the deformation amount of the steel type corresponding to Comparative Example 1 having the largest deformation amount is set as 1, and the ratio with the deformation amount is represented.

  As a result of the experiment, in Example 1, the deformation ratio was 0.10. In Example 2, the deformation amount ratio was 0.09. In Example 3, the deformation amount ratio was 0.05. In Example 4, the deformation amount ratio was 0.01. In Example 5, the deformation amount ratio was 0.01. In Comparative Example 2, the deformation amount ratio was 0.95.

  As is apparent from this, austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, 15 to 26% Cr in mass%, corresponding to Examples 1, 2, 3, 4, and 5. The deformation ratio of the separator plate using steel was significantly smaller than those of Comparative Examples 1 and 2. This is because the separator plate according to the present invention is made of austenitic stainless steel without ferrite / austenite transformation, so that deformation due to transformation due to transformation is reduced even if a local heat spot is formed on the separator plate. Because. As a result, it can be seen that smooth power transmission can be maintained between the separator plate and the friction plate, and that the separator plate and the friction plate can be prevented from prematurely deteriorating.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, as described above, the structure shown in the drawings when carrying out the present invention is the same as that of a conventionally known wet multi-plate clutch. Although omitted, the number of separator plates and the number of friction plates are not limited to the illustrated five separator plates and four friction plates, and the capacity of the transmission equipped with the wet multi-plate clutch is not limited. Is selected and set.

It is sectional drawing of the wet multi-plate clutch in the automatic transmission of one Embodiment which concerns on this invention. It is a front view of the separator plate used for the wet multi-plate clutch shown in FIG. It is a front view of the modification in the separator plate shown in FIG. It is a measurement data table of an example.

Explanation of symbols

10 Wet multi-plate clutch (wet multi-plate clutch in automatic transmission)
13 Friction plate 14 Friction member 15 Separator plate 23 Oil hole

Claims (2)

In the wet multi-plate clutch in the automatic transmission that includes the wet multi-plate clutch that contacts and separates the predetermined rotation element of the planetary gear unit and the input member,
The wet multi-plate clutch has a friction plate having a friction member on the surface, and a separator plate that slides on the surface of the friction member of the friction plate and transmits a rotational force,
The separator plate is formed of austenitic stainless steel of 0.50 to 10% Mn, 3.0 to 27% Ni, and 15 to 26% Cr in mass%, and is wet in an automatic transmission. Plate clutch.   2. The wet multi-plate clutch for an automatic transmission according to claim 1, wherein the separator plate has a plurality of circumferentially arranged oil holes through which oil passes.

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