JP2011102645A - Wet friction material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a more significant drag torque reduction effect certainly even in a case of a specification that there is no lubricating oil supply from an inner peripheral side or in a case that stirring torque increases by generating oil retained at an outer periphery. <P>SOLUTION: As for drag torque generated by rotation of a ring type friction material 6, and interaction with ATF (R) (Automatic Transmission Fluid) retained in the outer periphery of the ring type friction material 6, one or both or a whole outer periphery side area of both corner parts in an outer periphery side of an island shaped portion 8 interposed between a plurality of oil grooves 9 is eliminated by R processing or chamfering processing, and the eliminated circumferential length of the outer periphery side of the island shaped portion 8 is set up such that one or more of width of outer peripheral openings of the plurality of oil grooves 9 with the island shaped portion 8 removed of the outer peripheral side interposed therebetween is four times or more of the thinnest portion of the oil groove 9, thus restraining stirring torque due to ATF (R) at the outer peripheral portion to thereby achieve the significant drag torque reduction effect. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a wet friction material that obtains torque by applying high pressure to the opposite surface in a state immersed in oil, and a ring-shaped friction material base material is bonded to both surfaces or one surface of a flat ring metal core. The present invention relates to a ring-type friction material formed by pressing or cutting both surfaces or one surface of a ring-shaped friction material to form a plurality of oil grooves in the radial direction.

  In recent years, as a wet friction material, a friction material that has been cut into segment pieces along a flat ring shape on a flat ring metal core with the aim of reducing costs by improving material yield and reducing fuel consumption in vehicles by reducing drag torque A segment type friction material has been developed, in which the base material is sequentially aligned with an adhesive at intervals to become oil grooves and bonded over the entire circumference, and the friction material base material cut into segment pieces is also bonded to the back surface. ing. Such a segment type friction material is a friction material engagement provided with a plurality or a single friction plate used in an automatic transmission (hereinafter abbreviated as “AT”) such as an automobile or a transmission such as a motorcycle. It can be used for devices.

  As an example, wet hydraulic clutches are used in automatic transmissions for automobiles, etc., and multiple segment type friction materials and multiple separator plates are alternately stacked, and torque is transmitted by pressure-contacting both plates with hydraulic pressure. In order to absorb frictional heat generated when shifting from the non-fastened state to the fastened state and to prevent wear of the friction material, lubricating oil (Automatic Transmission Fluid) Lubricating oil, hereinafter also referred to as “ATF”). (“ATF” is a registered trademark of Idemitsu Kosan Co., Ltd.)

  However, in order to increase the response of the hydraulic clutch, the distance between the segment type friction material and the separator plate which is the counterpart material is set small, and in order to sufficiently secure the torque transmission capacity when the hydraulic clutch is engaged, The total area of the oil passage on the segment type friction material is limited. As a result, the ATF remaining between the segment type friction material and the separator plate is difficult to be discharged when the hydraulic clutch is not engaged, and there is a problem that drag torque due to ATF is generated by the relative rotation of both plates.

  Therefore, in Patent Document 1, an oil groove formed between adjacent segment pieces is defined, and the wet friction member is characterized in that the interval between the oil grooves is narrowed on the way from the inner peripheral side to the outer peripheral side. This invention is disclosed. As a result, the ATF flowing from the inner peripheral side to the outer peripheral side is blocked at the point where the oil groove interval changes, and a part of the ATF overflows the surface of the segment piece and flows through the surface of the segment piece. The cooling effect is improved, the heat resistance is improved, and the drag torque can be reduced.

  Further, in the invention described in Patent Document 2, since the two sides to which the opposite direction R is attached to the core of the segment piece are bonded so as to be the inner periphery and the outer periphery, the oil groove direction is formed on the inner periphery. And the width of the outer peripheral opening of the gap serving as the oil groove is larger than the width of the inner peripheral opening, thereby greatly improving the ATF discharge performance due to the idling of the segment type friction material, The drag torque by ATF is said to be greatly reduced.

  Furthermore, in the invention described in Patent Document 3, the segment type friction material is rotated in a non-fastened state when incorporated into the AT by cutting off the inner peripheral side angle of the segment piece at a predetermined angle in the segment type friction material. When the ATF supplied from the inner peripheral side comes into contact with the cut-off portion of the segment piece, the ATF is positively supplied to the friction surface of the friction material base, and the contact between the separator plate and the friction surface The drag torque caused by ATF is greatly reduced.

Further, in Patent Document 4, in the segment type friction material, in order to prevent the segment piece from peeling off due to an increase in the hydraulic pressure of the ATF that contacts the side surface of the segment piece (the surface constituting the oil groove), An invention is disclosed in which R is added to four corners, or four corners of a segment piece are chamfered. As a result, it is considered that the peel resistance is greatly improved, and when the shapes of the four corners are appropriate, the drag torque due to the ATF is reduced.
JP 2001-295859 A Japanese Patent Laying-Open No. 2005-06941 JP 2005-282648 A JP 2004-150449 A

  However, in the techniques described in Patent Document 1 to Patent Document 3, it is assumed that ATF is supplied from the inner peripheral side of the core of the segment type friction material, and in the actual machine, ATF is supplied from the hub hole. When there is no specification, or when the oil accumulation is generated on the outer periphery and the stirring torque becomes large, the effect of reducing the drag torque is still small, and it is difficult to realize significant fuel efficiency reduction in the vehicle There was a point.

  Moreover, in the technique of the said patent document 4, since it aims only at preventing that a segment piece peels, R and chamfering of four corners of the segment piece shown by embodiment are carried out. The effect of reducing drag torque cannot be obtained because it is too small, and an appropriate range of R and chamfer size at the four corners of the segment piece for reducing drag torque is not shown. Furthermore, there is a problem in that all four corners of the segment piece must be R-processed or chamfered, which is not always required to reduce drag torque.

  Therefore, the present invention reliably obtains a large drag torque reduction effect even when the specification is such that there is no supply of lubricating oil from the inner periphery side or when the oil pool is generated on the outer periphery and the stirring torque increases. It is an object of the present invention to provide a wet friction material that can be used.

  The wet friction material according to the invention of claim 1 is formed by pressing or cutting a ring-shaped friction material base material on both sides or one side of a flat ring-shaped cored bar, leaving an island-shaped portion in a radial direction. A wet friction material of a ring type friction material in which a plurality of oil grooves are formed, and is generated by the interaction with the lubricating oil accumulated on the outer periphery of the ring type friction material when the ring type friction material rotates. One or both of the outer peripheral side corners of the island-shaped portion sandwiched between the plurality of oil grooves or the entire outer peripheral side is deleted by R machining or chamfering, and the outer peripheral side of the island-shaped portion is deleted. The circumferential length is set so that one or more of the widths of the outer peripheral openings of the plurality of oil grooves sandwiching the island-like portion from which the outer peripheral side is removed is four times or more the narrowest part of the oil grooves. What was done A.

  The wet friction material according to a second aspect of the present invention is the wet friction material according to the first aspect, wherein a concave portion that is recessed with respect to the outer peripheral side is provided at the outer peripheral side central portion of the island-shaped portion.

  The wet friction material according to the invention of claim 1 is formed by pressing or cutting a ring-shaped friction material base material on both sides or one side of a flat ring-shaped cored bar, leaving an island-shaped portion in a radial direction. A wet friction material of a ring type friction material in which a plurality of oil grooves are formed, and the drag torque generated by the interaction with the lubricating oil accumulated on the outer periphery of the ring type friction material when the ring type friction material rotates. The outer peripheral side of the island-like portion sandwiched between the plurality of oil grooves is deleted to facilitate the circulation of the lubricating oil to the outer periphery of the ring type friction material.

  That is, by removing the outer peripheral side of the island-shaped part, it becomes easier for the lubricating oil to circulate to the outer periphery of the ring-type friction material, thereby interacting with the lubricating oil that accumulates on the outer periphery when the ring-type friction material rotates. The drag torque generated by can be reduced.

  With such a configuration, when the wet friction material idles in any direction in the non-fastened state, the lubricant supplied from the outer peripheral side of the wet friction material in the case of a specification in which no lubricant is supplied from the inner peripheral side In order to secure the space between the wet friction material and the separator plate by damming up at the portion where the is removed and overflowing to the surface of the island-shaped portion, only the wet friction material smoothly idles. Also, in the case of the specification in which the lubricating oil is supplied from the inner peripheral side, the outer peripheral side of the island-shaped portion is deleted, so that there is sufficient space for the lubricating oil to flow on the outer periphery of the wet friction material. It is possible to reliably prevent a situation where an oil reservoir is generated and drag torque increases.

  Moreover, one or both of the outer peripheral side corners of the island-shaped part are R-processed or chamfered. That is, the opening part on the outer peripheral side of the plurality of oil grooves extends in a curved line or linearly, and the expanded part in which the lubricating oil flowing from the outer peripheral side of the wet friction material is a part subjected to R processing or chamfering processing In this way, it is easy to overflow the surface of the island-like portion, and a sufficient space for lubricating oil to flow around the outer periphery of the wet friction material is secured.

  When the wet friction material idles in either direction in the non-engaged state, the lubricating oil supplied from the outer peripheral side of the wet friction material spreads in the case of a specification in which no lubricating oil is supplied from the inner peripheral side. In order to secure the space between the wet friction material and the separator plate by being dammed up by the raised portion and overflowing to the surface of the island-shaped portion, only the wet friction material is smoothly idled. Also, in the case of the specification in which the lubricating oil is supplied from the inner peripheral side, there is a sufficient space for the lubricating oil to flow on the outer periphery of the wet friction material, so that an oil pool is generated on the outer peripheral and the drag torque increases. It can be surely prevented.

  Furthermore, an R region or a chamfering process is performed on substantially the entire outer peripheral side of the island-shaped portion. That is, the openings on the outer peripheral side of the plurality of oil grooves are extended over the entire outer peripheral side in a curved or linear manner, and the lubricating oil flowing from the outer peripheral side of the wet friction material is R-processed or chamfered. In addition to being dammed up by the expanded part, which is a part of the wet part, the surface of the island part is easily overflowed, and a sufficient space for the lubricating oil to flow around the outer periphery of the wet friction material is secured.

  In addition, the length of the outer peripheral side of the island-shaped portion is deleted so that one or more of the widths of the outer peripheral openings of the plurality of oil grooves sandwiching the island-shaped portion from which the outer peripheral side is deleted is four times or more the narrowest portion of the oil groove. Since the outer peripheral openings of the plurality of oil grooves are expanded to a width that is at least four times the width of the narrowest part of the oil grooves, the drag torque can be further reliably reduced. An effect can be obtained.

  In this way, even in the case of specifications where there is no supply of lubricating oil from the inner periphery side or when an oil pool is generated on the outer periphery and the agitation torque is increased, the effect of reducing the larger drag torque can be further ensured. It becomes the wet friction material which can be obtained.

  In the wet friction material according to the second aspect of the present invention, a concave portion that is recessed with respect to the outer peripheral side is provided in the central portion on the outer peripheral side of the island-shaped portion. As a result, the lubricating oil supplied from the outer peripheral side overflows not only from the R-processed or chamfered part but also from the concave part to the surface of the island-like part, so that a greater drag torque reduction effect can be obtained. Since the space in which the lubricating oil on the outer periphery of the wet friction material flows becomes wider, it is possible to more reliably prevent a situation where an oil pool is generated on the outer periphery and the drag torque increases.

Embodiments of the present invention will be described below with reference to the drawings.
In the first embodiment, the same symbols and the same reference numerals as those of the reference example mean the same or corresponding functional parts as those of the reference example, and the same symbols and the same reference signs as those of the embodiment are those Since it is a functional part common to the reference example and the embodiment, the detailed description which overlaps is omitted here.

Reference Example First, a wet friction material according to a reference example of the present invention will be described with reference to FIGS.
FIG. 1A is a partial plan view showing a part of a wet friction material (case 1) according to a reference example of the present invention, and FIG. 1B is a wet friction material according to a first modification of the reference example of the present invention ( (C) is a partial plan view showing a part of a wet friction material (case 3) according to a second modification of the reference example of the present invention. FIG. 2A is a partial cross-sectional view showing a longitudinal section of a wet friction material (case 1) according to a reference example of the present invention, and FIG. 2B is a view of a wet friction material according to a third modification of the reference example of the present invention. It is the fragmentary sectional view which showed the longitudinal cross section. FIGS. 3A and 3B are partial plan views showing a part of a wet friction material according to another modification of the reference example of the present invention. 4 (a), (b), (c), (d), (e), and (f) show the shape of a segment piece used in a wet friction material according to another modification of the reference example of the present invention. It is a top view.

  FIG. 5A is a partial plan view showing a part of a wet friction material according to a fourth modification of the reference example of the present invention, and FIG. 5B is a wet friction material according to the fifth modification of the reference example of the present invention. (C) is a partial plan view showing a part of a wet friction material according to a sixth modification of the reference example of the present invention, and (d) is a partial plan view of the reference example of the present invention. FIG. 7E is a partial plan view showing a part of a wet friction material according to a seventh modification, and FIG. 9E is a partial plan view showing a part of the wet friction material according to an eighth modification of the reference example of the present invention.

  6A is a partial plan view showing a part of the wet friction material according to the first example of the prior art (Comparative Example 1), and FIG. 6B is a wet friction material according to the second example of the prior art (Comparative Example). 2) is a partial plan view showing a part of (2), and (c) is a partial plan view showing a part of a wet friction material (Comparative Example 3) according to a third example of the prior art. FIG. 7 shows the relationship between the relative rotational speed and drag torque of the wet friction material (cases 1, 2, 3) according to the reference example of the present invention in comparison with the conventional wet friction material (comparative examples 1, 2, 3). FIG. FIG. 8 is a diagram showing the relationship between parameters in the wet friction material (case 1) according to the reference example of the present invention.

  FIG. 9 is a graph showing the relationship between the cutting height (radial width) of the outer peripheral corner of the oil groove and the drag torque reduction rate in the wet friction material (case 1) according to the reference example of the present invention. FIG. 10 is a diagram showing the relationship between the cut length (circumferential width) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (case 1) according to the reference example of the present invention. FIG. 11A is an explanatory diagram showing the generation of drag torque in a conventional wet friction material (Comparative Example 1), and FIG. 11B is an effect of reducing drag torque in a wet friction material (Case 1) according to a reference example of the present invention. It is explanatory drawing which shows.

  As shown in FIG. 1 (a), a segment type friction material 1 as a wet friction material (case 1) according to a reference example is formed on a core metal 2 made of a flat plate ring-shaped steel plate and a normal friction friction material 1 is used. A plurality of segment pieces 3 obtained by cutting out the friction material base material are pasted and pasted at intervals of the oil grooves 4 using an adhesive (thermosetting resin), and the back surface of the core metal 2 is also similarly adhesive. It is what is pasted. Here, the left and right outer peripheral corners of the segment piece 3 have a notch 3a whose height (the width in the radial direction of the segment type friction material 1) is α mm and whose length (the width in the circumferential direction of the segment type friction material 1) is β mm. Is provided.

  That is, in the segment type friction material 1 as the wet friction material (case 1) according to the reference example, both the outer peripheral side corners of the segment piece 3 sandwiched between the plurality of oil grooves 4 are chamfered. All of the oil grooves 4 have a symmetrical shape, and all of the outer peripheral openings of the plurality of oil grooves 4 have a symmetrical shape and are at least four times the width of the narrowest portion of the plurality of oil grooves 4. It has spread to.

  Moreover, as shown in FIG.1 (b), the segment type friction material 1A as a wet friction material (example 2) which concerns on the 1st modification of a reference example is the core metal 2 made from a flat ring-shaped steel plate, A plurality of segment pieces 3A, 3B cut out from a normal friction material base material for wet friction materials are pasted alternately using an adhesive (thermosetting resin) at intervals of oil grooves 4A, 4B. The back surface of the cored bar 2 is similarly attached with an adhesive. Here, the left outer peripheral corner of the segment piece 3A and the right outer peripheral corner of the segment piece 3B each have a height (the width in the radial direction of the segment type friction material 1A) and a length (segment type friction material). Cuts 3Aa and 3Ba having a width of 1A in the circumferential direction) are provided.

  That is, in the segment type friction material 1A as the wet friction material (case 2) according to the first modification of the reference example, the outer peripheral side corners of the segment pieces 3A and 3B sandwiched between the plurality of oil grooves 4A and 4B. One is chamfered, and all of the plurality of oil grooves 4A, 4B have a bilaterally symmetric shape, and every other one of the plurality of oil grooves 4A, 4B has a bilaterally symmetric shape with a plurality of symmetric shapes. There is provided an oil groove 4A that expands to a width that is four times or more the width of the narrowest part of the oil grooves 4A, 4B.

  Further, as shown in FIG. 1 (c), a segment type friction material 1C as a wet friction material (example 3) according to a second modification of the reference example is formed on a metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 3C obtained by cutting out a normal friction material base material for wet friction materials are pasted and pasted with an interval of oil grooves 4C using an adhesive (thermosetting resin). In the same manner, it is affixed with an adhesive. Here, the left and right outer peripheral corners of the segment piece 3C have a height (width in the radial direction of the segment type friction material 1C) of (α1) mm and a length (width in the circumferential direction of the segment type friction material 1C) of 50. % Cut 3Ca is provided. That is, the outer peripheral side of the segment piece 3C is completely cut off from the left and right. Then, α1 = (3/4) α.

  That is, in the segment type friction material 1C as the wet friction material (example 3) according to the second modified example of the reference example, both the outer corners of the segment piece 3C sandwiched between the plurality of oil grooves 4C are chamfered. All of the plurality of oil grooves 4C have a symmetrical shape, and all of the outer peripheral openings of the plurality of oil grooves 4C have a symmetrical shape with the width of the narrowest part of the plurality of oil grooves 4C. It spreads over 4 times.

  Here, the structure of the longitudinal section of the wet friction material (case 1) according to the reference example and the structure of the longitudinal section of the wet friction material according to the third modification of the reference example will be described with reference to FIG. As shown in FIG. 2A, in the segment type friction material 1 as the wet friction material (example 1) according to the reference example, the circumferential direction of the segment piece 3 on the front surface side and the back surface side of the core metal 2 Accordingly, the positions of the oil grooves 4 in the circumferential direction are substantially the same on the front and back sides.

  On the other hand, as shown in FIG. 2B, in the segment type friction material 1F as the wet friction material according to the third modification of the reference example, the segment pieces are formed on the front surface side and the back surface side of the core metal 2. 3 is shifted in the circumferential direction, and therefore the position of the oil groove 4 in the circumferential direction is also shifted between the front and back sides.

  That is, the bonding position of the segment piece 3 and the position of the oil groove 4 in the circumferential direction may be random on the front and back of the core metal 2, and the core as in the segment type friction material 1 shown in FIG. The front and back of the gold 2 may coincide with each other, or the front and back of the core metal 2 may be displaced as in the segment type friction material 1F shown in FIG. The same applies to the other segment type friction materials described in the reference example.

Next, a wet friction material according to another modification of the reference example will be described with reference to FIG.
As shown in FIG. 3 (a), a segment type friction material 1D as a wet friction material according to another modified example of the reference example is formed on a metal core 2 made of a flat plate ring-shaped steel plate and is usually used for a wet friction material. A plurality of segment pieces 3, 3A, 3B obtained by cutting out the friction material base material of the above are arranged and pasted at intervals of oil grooves using an adhesive (thermosetting resin), and the same is applied to the back surface of the core metal 2 Affixed with an adhesive.

  Here, in FIG. 3 (a), (b), the oil groove provided between the segment piece 3 and the segment piece 3A, and the oil groove provided between the segment piece 3 and the segment piece 3B ( In any case, the outer peripheral opening has a left-right symmetric shape and spreads to a width that is at least four times the width of the narrowest portion of the plurality of oil grooves).

  As shown in FIG. 3A, in the segment type friction material 1D, after the two segment pieces 3 are pasted, two segment pieces 3A and two segment pieces 3B are pasted alternately. It is repeated over the circumference. As a result, three oil grooves 4D, 4 and 4D, which have a symmetrical outer peripheral opening and have a width that is four times the width of the narrowest part of the plurality of oil grooves, are continuously arranged, and the outer peripheral opening is One oil groove 4B that is not expanded is arranged with one oil groove 4B that is not expanded, and one oil groove 4B that is not expanded with the outer periphery opening is further interposed, and the outer periphery opening is expanded. Three oil grooves 4D, 4 and 4D are continuously arranged.

  Further, as shown in FIG. 3 (b), a segment type friction material 1E as a wet friction material according to another modified example of the reference example is provided on a core metal 2 made of a flat plate ring-shaped steel plate and used for a wet friction material. A plurality of segment pieces 3, 3A, 3B cut out from the normal friction material base material are pasted and pasted at intervals of oil grooves using an adhesive (thermosetting resin). Is also affixed with an adhesive.

  As shown in FIG. 3 (b), in the segment type friction material 1E, the segment piece 3, the segment piece 3A, and the segment piece 3B are sequentially attached in the clockwise direction (clockwise), and this extends over the entire circumference. It has been repeated. As a result, two oil grooves 4D that have a circumferentially symmetric shape of the outer peripheral opening and that extend to a width of four times or more the width of the narrowest part of the plurality of oil grooves are continuously arranged, and the outer peripheral opening is not expanded. Two oil grooves 4 </ b> D having one groove 4 </ b> B sandwiched between them and the outer peripheral opening portion being expanded are arranged in a row.

  Furthermore, the shape of the segment piece used for the wet friction material which concerns on the other modification of a reference example is demonstrated with reference to FIG.

  The segment piece 3D shown in FIG. 4 (a) is R-processed at both outer corners, and the segment piece 3E shown in FIG. 4 (b) has both outer corners shown in FIG. The segment piece 3F shown in FIG. 4 (c) is rounded to the middle portion of the outer periphery.

  In addition, the segment piece 3G shown in FIG. 4 (d) is provided with a recess 3g having a width gmm that is recessed with respect to the outer peripheral side at the outer peripheral side central portion, while both of the outer peripheral corners are chamfered. The segment piece 3H shown in FIG. 4 (e) is R-processed at both corners on the outer peripheral side and is provided with a concave portion 3h having a width hmm that is recessed with respect to the outer peripheral side at the central portion of the outer peripheral side. The segment piece 3I shown in (f) is chamfered at both corners on the outer peripheral side, and is provided with a recess 3i having a width imm that is recessed with respect to the outer peripheral side at the central portion on the outer peripheral side.

  Accordingly, in the segment type friction material using these segment pieces 3G, 3H, and 3I, the lubricating oil supplied from the outer peripheral side is not only from the R processing or chamfering portion but also from the recesses 3g, 3h, and 3i. Since it overflows to the surface of the segment pieces 3G, 3H, 3I, it is possible to obtain a greater drag torque reduction effect, and a wider space for the lubricating oil on the outer periphery of the wet friction material to be increased. It is possible to more reliably prevent a situation where an oil reservoir is generated and drag torque increases.

Furthermore, a wet friction material according to another modification of the reference example will be described with reference to FIG.
As shown in FIG. 5 (a), a segment type friction material 1G as a wet friction material according to a fourth modification of the reference example is a normal type for a wet friction material on a metal core 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 3J obtained by cutting out the friction material base material are pasted with an adhesive (thermosetting resin) at intervals of the oil grooves 4E, and the adhesive is similarly applied to the back surface of the core metal 2. It is made by pasting with. The segment piece 3J is larger in height (radial width) and length (circumferential width) than the above-described segment piece 3 and the like, so the number of oil grooves 4E is 30 on the entire circumference. It is less than the segment type friction material 1 described above.

  Here, the left and right outer peripheral corners of the segment piece 3J are cut (chamfered) 3Ja, and the central part of the outer periphery of the segment piece 3J has a recess 3j having a width jmm that is recessed with respect to the outer peripheral side. Is provided.

  Thereby, the segment type friction material 1G has the effect of reducing the drag torque more reliably because the lubricant supplied from the outer peripheral side overflows not only from the chamfered portion 3Ja but also from the recess 3j to the surface of the segment piece 3J. In addition, since the space through which the lubricating oil on the outer periphery of the segment type friction material 1G flows becomes wider, it is possible to more reliably prevent a situation where an oil reservoir is generated on the outer periphery and drag torque increases. .

  Further, as shown in FIG. 5 (b), a segment type friction material 1H as a wet friction material according to a fifth modification of the reference example is provided on a core metal 2 made of a flat plate ring-shaped steel plate for a wet friction material. A plurality of segment pieces 3K, 3L cut out of the normal friction material base material are bonded and arranged alternately with an adhesive (thermosetting resin) at intervals of the oil grooves 4F, 4G. Similarly, it is affixed to the back surface of 2 with an adhesive. The segment pieces 3K and 3L are larger in height (radial width) than the above-described segment pieces 3 and the like, but have the same length (circumferential width). Therefore, the oil grooves 4F, The number of 4G is 40 on the entire circumference, which is the same as the segment type friction material 1 described above.

  Here, the right outer peripheral corner of the segment piece 3K is chamfered 3Ka over almost the entire outer surface of the segment piece 3K, and the left outer peripheral corner of the segment piece 3L has a segment piece 3L. A chamfering process 3La is applied over substantially the entire outer peripheral side of the plate.

  Moreover, as shown in FIG.5 (c), the segment type friction material 1J as a wet friction material which concerns on the 6th modification of a reference example is used for the wet friction material to the metal core 2 made from a flat ring metal plate. A plurality of segment pieces 3K, 3L, 3M, and 3N cut out from the normal friction material base material are arranged in this order in the clockwise direction (clockwise), and an oil groove is formed using an adhesive (thermosetting resin). 4F, 4H, 4J, and 4K are pasted at intervals, and the back surface of the cored bar 2 is similarly pasted with an adhesive.

  Here, a cut (chamfering) 3Ma is applied to the right outer peripheral corner of the segment piece 3M, and a cut (chamfering) 3Na is applied to the left outer peripheral corner of the segment piece 3N.

  Further, as shown in FIG. 5D, a segment type friction material 1K as a wet friction material according to a seventh modification of the reference example is provided on a core metal bar 2 made of a flat plate ring-shaped steel plate and used for a wet friction material. A plurality of segment pieces 3K cut out of the normal friction material base material are pasted and pasted at intervals of the oil grooves 4L using an adhesive (thermosetting resin), and similarly on the back surface of the core metal 2 Attached with an adhesive.

  Further, as shown in FIG. 5 (e), a segment type friction material 1L as a wet friction material according to an eighth modification of the reference example is provided on a metal core 2 made of a flat plate ring-shaped steel plate and used for a wet friction material. A plurality of segment pieces 3L and 3M cut out of the normal friction material base material are bonded and arranged alternately with an interval between the oil grooves 4H and 4M using an adhesive (thermosetting resin). Similarly, it is affixed to the back surface of 2 with an adhesive.

  As a result, these segment type friction materials 1H, 1J, 1K, and 1L are surely more reliable because the lubricating oil supplied from the outer peripheral side overflows from the chamfered portion to the surface of the segment pieces 3K, 3L, 3M, and 3N. A large drag torque reduction effect can be obtained, and the space where the lubricating oil flows on the outer periphery of the wet friction material becomes wider, so it is possible to more reliably prevent the drag torque from increasing due to an oil pool on the outer periphery. can do.

Next, a segment type friction material as a wet friction material according to the prior art will be described with reference to FIG.
As shown in FIG. 6 (a), a segment type friction material 11 as a wet friction material (Comparative Example 1) according to a first example of the prior art is applied to a metal core 2 made of a flat plate ring-shaped steel plate. A plurality of segment pieces 13 obtained by cutting out a normal friction material base material for a material are attached with an oil groove 14 spaced apart using an adhesive (thermosetting resin). Similarly, it is affixed with an adhesive. The segment type friction material 11 according to the first example of the related art having such a configuration corresponds to an example of the segment type friction material according to the invention of Patent Document 4.

  Further, as shown in FIG. 6 (b), the segment type friction material 11A as the wet friction material (Comparative Example 2) according to the second example of the prior art is formed on a metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 13A and 13B obtained by cutting out a normal friction material base material for wet friction materials are pasted alternately using an adhesive (thermosetting resin) at intervals of oil grooves 14A and 14B. The back surface of the cored bar 2 is similarly attached with an adhesive.

  Here, each of the left inner peripheral corner of the segment piece 13A and the right inner peripheral corner of the segment piece 13B has a height (segment type friction material 11A radial width) of α mm and a length (segment type). Cuts 13 </ b> Aa and 13 </ b> Ba having a width of β mm of the friction material 11 </ b> A in the circumferential direction are provided. 11 A of segment type friction materials which concern on the 2nd example of the prior art of this structure correspond to an example of the segment type friction material which concerns on the invention of the said patent document 3. FIG.

  Further, as shown in FIG. 6 (c), the segment type friction material 11C as the wet friction material (Comparative Example 3) according to the third example of the prior art is formed on the metal core 2 made of a steel plate having a flat ring shape. A plurality of segment pieces 13C obtained by cutting out a normal friction material base material for wet friction materials are pasted with an adhesive (thermosetting resin) at intervals of oil grooves 14C, and the back surface of the core metal 2 is attached. In the same manner, it is affixed with an adhesive. The segment type friction material 11C according to the third example of the related art having such a configuration corresponds to an example of the segment type friction material according to the invention of Patent Document 2.

  Of the segment type friction materials according to the reference example described above, the segment type friction material 1 (case 1), the segment type friction material 1A according to the first modification example (example 2), and the segment type friction material according to the second modification example. 1C (Case 3), segment type friction material 11 according to the first example of the prior art (Comparative Example 1), segment type friction material 11A according to the second example of the prior art (Comparative Example 2), and second of the prior art About the segment type friction material 11C (comparative example 3) which concerns on an example, the relationship between relative rotation speed and drag torque was verified by the test.

  The size of each segment piece is as follows: the width of the segment piece = 13 mm, the vertical width of the segment piece 3 = 5 mm, the number of segment pieces is 40 on one side (80 on both sides), and the width of the narrowest part of the oil groove is 1 mm. α = 2 mm and β = 2 mm. That is, in the segment piece 3, the circumferential width (2 mm) of the chamfering process is 15.4% of the circumferential width (13 mm) of the segment piece 3, and the radial width (2 mm) of the chamfering process. Is 40% of the radial width (5 mm) of the segment piece. The same applies to the segment pieces 3A and 3B.

  Further, in the segment piece 3C, the circumferential width (6.5 mm) of the chamfering process is 50% of the circumferential width (13 mm) of the segment piece 3, and the radial width (α1 = chamfering process). (3/4) α = (3/4) × 2 mm = 1.5 mm) is 30% of the radial width (5 mm) of the segment piece.

  As test conditions, the relative rotational speed = 500 to 7000 rpm, ATF oil temperature = 40 ° C., ATF oil amount = 500 mL / min (without shaft center lubrication), disk size shown in FIGS. 1 and 3, outer periphery φ1 = 185 mm, The test was performed at an inner circumference φ2 = 175 mm, and the number of disks was 7 (therefore, 8 steel plate disks were used as mating members) and the pack clearance was 0.25 mm / sheet. The result of the test is shown in FIG.

  As shown in FIG. 7, when the relative rotational speed is 500 rpm, there is already a large difference between cases 1, 2, and 3 and comparative examples 1 and 2, and reference examples (cases 1, 2, The segment type friction materials 1, 1A and 1C according to 3) have a smaller drag torque than the segment type friction materials 11, 11A and 11C according to Comparative Examples 1, 2 and 3.

  After that, as the relative rotational speed increases, the dragging torque decreases for any segment type friction material because the condition is that there is no shaft center lubrication. However, at the time when the relative rotational speed is 1000 rpm, 1500 rpm, 2000 rpm, Case 1 , 2, 3 and the comparative examples 1, 2, 3 are maintained. At the time when the relative rotational speed is 2500 rpm, there is almost no difference between the cases 1, 2, 3 and the comparative examples 1, 3, but only the comparative example 2 still has a large drag torque, up to 7000 rpm. The drag torque remains larger than 1, 2, 3.

  Thus, the segment type friction materials 1, 1A, 1C according to the reference examples (cases 1, 2, 3) are the same as the segment type friction materials 11, 11A, 11C (comparative examples 1, 2, 3) according to the prior art. In comparison, it was demonstrated that the drag torque reduction effect is large.

  In addition, as shown in FIG. 7, the segment type friction material 1C according to the example 3 is more suitable for the segment type according to the examples 1 and 2 over the entire range of the relative rotation speed = 500 to 7000 rpm. The result shows that the drag torque is smaller than that of the friction materials 1 and 1A. Therefore, among the segment type friction materials 1, 1A, 1C according to the reference example, the segment type friction material 1C, that is, the segment type friction material that is chamfered symmetrically to the center on the outer peripheral side of the segment piece. However, it was found that the drag torque reduction effect is greater.

  Accordingly, in order to obtain a larger drag torque suppression effect, the segment type friction material 1 of the reference example shown in FIG. 8 and the six parameters related to the segment piece 3 used for the segment type friction material 1, that is, the height of the cut 3a. (Width in radial direction) α, Length of cut 3a (Width in circumferential direction) β, Width of thinnest portion of oil groove 4, γ of segment piece 3, horizontal width δ of segment piece 3, vertical width ε of segment piece 3, oil groove An experiment was conducted to find the optimum values for the width σ of the outer peripheral opening 4.

  Among them, the bar graphs of FIGS. 9 and 10 show the experimental results for the height α and the length β of the cut 3a. First, in order to obtain the optimum value of the height α of the notch 3a, a sample with the notch length β = 2.0 mm fixed and the notch height α varied in four ways was prepared and incorporated in the AT actual machine, The drag torque reduction rate was measured.

  The drag torque reduction rate is expressed as an average value of two measured values when the rotation speed of the segment type friction material 1 is 1000 rpm and 1500 rpm. Then, when the cutting height α = 2 mm and the cutting length β = 2.0 mm, that is, in the case of the case 1 shown in FIG. The case where the drag torque reduction rate is reduced is indicated as minus.

  As for other parameters shown in FIG. 8, the width γ = 1 mm of the thinnest portion of the oil groove 4, the horizontal width δ = 13 mm of the segment piece 3, and the vertical width ε = 5 mm of the segment piece 3, , ATF oil temperature = 40 ° C., ATF oil amount = 500 mL / min (no shaft center lubrication), disk size tested at outer circumference φ1 = 185 mm, inner circumference φ2 = 175 mm, and the number of disks = 7 Eight steel plate disks) and pack clearance = 0.25 mm / sheet.

  As a result, as shown in FIG. 9, when the cutting height α is 1.0 mm and 1.5 mm, which is smaller than the case 1, the drag torque reduction rate decreases and becomes a negative value. When the height α was 2.5 mm, which was larger than that of Example 1, the value was positive. As a result, it is considered that the drag torque reduction effect improves as the cutting height α increases.

  On the other hand, in order to obtain the optimum value of the length β of the cut 3a, a sample with the cut height α fixed at 2.0 mm and the cut length β changed in four ways was built into the AT actual machine, The drag torque reduction rate was measured under the same test conditions. As a result, as shown in FIG. 10, when the cutting length β is 1.0 mm and 1.5 mm, which is smaller than the case 1, the drag torque reduction rate decreases and becomes a negative value. When the length β was 2.5 mm, which was larger than the case 1, the value was positive. As a result, it is considered that the drag torque reduction effect improves as the cut length β increases.

  Furthermore, as a result of repeated experiments on the relationship between the other parameters shown in FIG. 8, the cutting height α = in the range of 25% to 50% of the vertical width ε of the segment piece 3, and the cutting length β ≦ 0. 5 × (lateral width δ of segment piece 3), width σ of outer peripheral opening of oil groove 4 ≧ 4 × (width γ of the thinnest portion of oil groove 4) The higher drag torque reduction effect It became clear that can be obtained.

  As described above, in the case where the specification is such that there is no supply of lubricating oil (ATF) from the inner peripheral side of the wet friction material (without axial center lubrication), that is, the lubricating oil is supplied only from the outer peripheral side of the wet friction material. In the case of a segment type friction material, ATF flows from the processed part to the surface of the segment piece by R-processing or chamfering one or both of the outer peripheral side corners of the segment piece, A high drag torque reduction effect is obtained due to the peeling-off effect.

  On the other hand, the case where lubricating oil (ATF) is supplied from the inner peripheral side of a wet friction material is demonstrated with reference to FIG. As shown in FIG. 11A, in the segment type friction material 11 as the wet friction material (Comparative Example 1) according to the first example of the prior art, the stirring torque due to ATF accumulated on the outer peripheral portion is large. The drag torque will increase.

  On the other hand, as shown in FIG. 11B, in the segment type friction material 1 as the wet friction material (case 1) according to the reference example, by providing a cut 3a on the outer periphery of the segment piece 3, The stirring torque by ATF can be suppressed, and the drag torque is reduced by the peeling effect that ATF flows from the notch 3a to the surface of the segment piece 3 and enters the mating material.

  As described above, when the lubricating oil is supplied only from the outer peripheral side, cutting the inner periphery of the segment piece has little effect of reducing the drag torque, but the lubricating oil (ATF) is supplied from the inner peripheral side. ), A higher drag torque reduction effect can be obtained by providing a cut on the outer periphery of the segment piece and also making a cut on the inner periphery of the segment piece.

  Thus, in the segment type friction materials 1, 1A and 1C as the wet friction materials according to the reference example, in the case of the specification (without the lubrication of the shaft core) in which the lubricating oil is not supplied from the inner peripheral side, Even in the case where an oil pool is generated and the stirring torque increases, a greater drag torque reduction effect can be obtained more reliably.

Embodiment 1
Next, the wet friction material according to Embodiment 1 of the present invention will be described with reference to FIGS. 12A is a partial plan view showing a part of the wet friction material according to Embodiment 1 of the present invention, and FIG. 12B shows a longitudinal section of the wet friction material according to Embodiment 1 of the present invention. Partial sectional view, (c) is a partial plan view showing a part of a wet friction material according to a first modification of the first embodiment of the present invention, and (d) is a second modification of the first embodiment of the present invention. It is the fragmentary top view which showed a part of wet friction material which concerns on an example.

  FIG. 13 (a) is a partial sectional view showing a longitudinal section of a wet friction material according to a third modification of the first embodiment of the present invention, and FIG. 13 (b) is a fourth modification of the first embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the fifth modification of the first embodiment of the present invention. FIG. 14A is a partial plan view showing a part of a wet friction material according to a sixth modification of the first embodiment of the present invention, and FIG. 14B shows a seventh modification of the first embodiment of the present invention. FIG. 8C is a partial plan view showing a part of the wet friction material, and FIG. 8C is a partial plan view showing a part of the wet friction material according to the eighth modification of the first embodiment of the present invention.

  12 (a) and 12 (b), the wet friction material 6 according to Embodiment 1 is different from the reference example (segment type friction material) on both surfaces of a core metal plate 2 made of a flat plate ring-shaped steel plate. By attaching a ring-shaped friction material base material 7 obtained by cutting out a normal friction material base material for wet friction material to the entire surface using an adhesive (thermosetting resin) and pressing both sides The ring-type friction material is formed by forming a plurality (40 on one side) of oil grooves 9 with the island-shaped portion 8 interposed therebetween.

  Here, the oil groove 9 is an oil groove in which the outer peripheral opening is expanded in a symmetrical shape, and both the outer peripheral side corners of the island-like portion 8 sandwiched between the plurality of oil grooves 9 to 9 are chamfered (8a The plurality of oil grooves 9 are all symmetric in shape, and the outer peripheral openings of the plurality of oil grooves 9 are symmetric, and the width of the narrowest part of the plurality of oil grooves 9 is It has spread to more than 4 times.

  Further, the radial height X (mm) and the circumferential direction of the chamfered portion 8a of the island-shaped portion 8 of the friction material base in the outer peripheral opening of the oil groove 9 in which the outer peripheral portion extends in a symmetrical shape. About length Y (mm), it was set as the same dimension as (alpha) and (beta) in the segment type friction material 1 which concerns on the said reference example. That is, X = 2 mm and Y = 2 mm.

  Furthermore, the horizontal width of the island-shaped portion 8 and the vertical width of the island-shaped portion 8 are the same dimensions as the segment piece 3 in the segment-type friction material 1 according to the reference example, that is, the island-shaped portion 8 The width in the horizontal direction = 13 mm and the width in the vertical direction of the island-shaped portion 8 = 5 mm.

  Further, as shown in FIG. 12C, the wet friction material 6A according to the first modification of the first embodiment is used for the wet friction material on the entire surface of both sides of the core metal plate 2 made of a flat plate ring shape. A ring-shaped friction material base material 7 cut out of a normal friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form island-shaped portions 8A and 8B. It is a ring type friction material formed with a plurality of (40 on one side) oil grooves 9A and 9B sandwiched therebetween. Here, the left outer peripheral corner portion of the island-shaped portion 8A and the right outer peripheral corner portion of the island-shaped portion 8B have a height (radial width) of Xmm and a length (circumferential width) of Ymm, respectively. Chamfering 8Aa and 8Ba are applied.

  That is, in the ring type friction material 6A as the wet friction material according to the first modification of the first embodiment, one of the corners on the outer peripheral side of the island portions 8A and 8B sandwiched between the plurality of oil grooves 9A and 9B. Are chamfered, and all of the plurality of oil grooves 9A, 9B have a symmetrical shape, and every other one of the plurality of oil grooves 9A, 9B has a symmetrical outer peripheral opening, and a plurality of oil grooves An oil groove 9A is provided that extends to a width that is at least four times the width of the narrowest part of the grooves 9A, 9B.

  Further, the width in the horizontal direction of the island-shaped portions 8A and 8B and the width in the vertical direction of the island-shaped portions 8A and 8B are the same as the segment piece 3 in the segment type friction material 1 according to the reference example, that is, the islands. The lateral width of the shaped portions 8A and 8B = 13 mm, and the longitudinal width of the island shaped portions 8A and 8B = 5 mm.

  Furthermore, as shown in FIG. 12 (d), the wet friction material 6C according to the second modification of the first embodiment is used for the wet friction material over the entire surface of the core metal 2 made of a flat plate ring-shaped steel plate. A ring-shaped friction material base material 7 cut out of a normal friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed, so that the island-shaped portion 8C is interposed therebetween. It is a ring type friction material formed by sandwiching a plurality (40 on one side) of oil grooves 9C. Here, the left and right outer peripheral corners of the island-like portion 8C are chamfered 8Ca with a height (radial width) of (X1) mm and a length (circumferential width) of 50%. That is, the outer peripheral side of the island-shaped portion 8C is completely cut off from the left and right. And X1 = (3/4) X.

  That is, in the ring-type friction material 6C as the wet friction material according to the second modification of the first embodiment, both the outer peripheral corners of the island-shaped portion 8C sandwiched between the plurality of oil grooves 9C are chamfered. Each of the plurality of oil grooves 9C has a symmetrical shape, and all the outer peripheral openings of the plurality of oil grooves 9C have a symmetrical shape, and the width of the narrowest portion of the plurality of oil grooves 9C is 4 It spreads more than double.

  Also, the horizontal width of the island-shaped portion 8C and the vertical width of the island-shaped portion 8C are the same dimensions as the segment piece 3 in the segment-type friction material 1 according to the reference example, that is, the island-shaped portion 8C. The width in the horizontal direction = 13 mm, and the width in the vertical direction of the island-shaped portion 8C = 5 mm.

  Next, a ring type friction material as a wet friction material according to a third modification, a fourth modification, and a fifth modification of the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 13 (a), the wet friction material 6D according to the third modified example of the first embodiment is different from the reference example (segment type friction material) in that the core metal 2 made of a steel plate having a flat ring shape. Bonding a ring-shaped friction material base material 7 obtained by cutting out a normal friction material base material for wet friction material onto both surfaces using an adhesive (thermosetting resin), and pressing both surfaces Thus, a ring type friction material is formed by forming a plurality (40 on one side) of oil grooves 9 with the island-like portion 8 interposed therebetween.

  Here, the ring type friction material 6D according to the third modification of the first embodiment is different from the ring type friction material 6 according to the first embodiment shown in FIGS. 12 (a) and 12 (b). In the ring type friction material 6, the positions where the island-like portions 8 are formed in the circumferential direction on the front surface side and the back surface side of the cored bar 2 substantially coincide with each other, and therefore the position of the oil groove 9 in the circumferential direction. In the ring type friction material 6D, the positions where the island-shaped portions 8 are formed in the circumferential direction on the front surface side and the back surface side of the core metal 2 are shifted. Therefore, the position of the oil groove 9 in the circumferential direction is also shifted on the front and back sides.

  That is, the position where the island-shaped portion 8 is formed in the circumferential direction and the position of the oil groove 9 may be random on the front and back of the cored bar 2, and the ring type shown in FIGS. 12 (a) and 12 (b). The front and back surfaces of the core metal 2 may coincide with each other as in the friction material 6, or the front and back surfaces of the core metal 2 may deviate like the ring type friction material 6 </ b> D shown in FIG. The same applies to the other ring type friction materials described in the first embodiment.

  Next, as shown in FIG. 13B, the ring type friction material 6E according to the fourth modification of the first embodiment is the same as the second modification of the first embodiment shown in FIG. The ring-type friction material 6C has an opposite outer peripheral shape with respect to the island-shaped portion 8C. That is, the island-shaped portion 8C of the ring-type friction material 6C has a convex shape on the outer peripheral side, whereas the island-shaped portion 8D of the ring-type friction material 6E has a width dmm that is recessed with respect to the outer peripheral side. 8 d of recesses. Further, chamfering 8Da is applied to the left and right outer corners of the island portion 8D.

  The island-shaped portion 8D is larger in height (radial width) and length (circumferential width) than the above-described island-shaped portion 8 and the like, and therefore the number of oil grooves 9D is 30 on the entire circumference. It is less than the book and the ring type friction material 6 described above. All of the plurality of oil grooves 9D have a symmetrical shape, and all the outer peripheral openings of the plurality of oil grooves 9D have a symmetrical shape and are four times or more the width of the narrowest portion of the plurality of oil grooves 9D. It spreads to the width.

  Further, as shown in FIG. 13 (c), the ring type friction material 6F as the wet friction material according to the fifth modification of the first embodiment is applied to the core metal 2 made of a steel plate having a flat ring shape. A ring-shaped friction material base material 10 obtained by cutting out a normal friction material base material for a material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form an island-shaped portion 8E. , 8F, and a plurality (40 on one side) of oil grooves 9E, 9F are formed. The island-like portions 8E and 8F are larger in height (radial width) than the above-described island-like portions 8 and the like, but have the same length (circumferential width). The number of 9E and 9F is 40 on the entire circumference, which is the same as that of the ring-type friction material 6 described above.

  Here, the right outer peripheral corner of the island-shaped portion 8E is chamfered 8Ea over almost the entire outer peripheral side of the island-shaped portion 8E, and the left outer peripheral corner of the island-shaped portion 8F is Chamfering 8Fa is performed over substantially the entire outer peripheral side of the island-shaped portion 8F.

  Next, a ring type friction material as a wet friction material according to a sixth modification, a seventh modification, and an eighth modification of the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 14 (a), the wet friction material 6G according to the sixth modification of the first embodiment is a normal one for a wet friction material on both surfaces of a core metal 2 made of a flat plate ring-shaped steel plate. The ring-shaped friction material base material 10 cut out from the friction material base material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form island portions 8E, 8F, 8G, It is a ring type friction material in which a plurality of (40 on one side) oil grooves 9E, 9G, 9H, 9J are formed with 8H interposed therebetween.

  Here, chamfering 8Ga is applied to the right outer peripheral corner of the island-shaped portion 8G, and chamfering 8Ha is applied to the left outer peripheral corner of the island-shaped portion 8H.

  Further, as shown in FIG. 14 (b), the ring type friction material 6H as the wet friction material according to the seventh modification of the first embodiment is formed on both surfaces of the core metal 2 made of a flat plate ring-shaped steel plate. A ring-shaped friction material base material 10 cut out from a normal friction material base material for a wet friction material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form islands. A plurality (40 on one side) of oil grooves 9K are formed with the shaped portion 8F interposed therebetween.

  Further, as shown in FIG. 14 (c), the ring type friction material 6J as the wet friction material according to the eighth modification of the first embodiment is formed on both surfaces of the core metal 2 made of a flat plate ring-shaped steel plate. A ring-shaped friction material base material 10 cut out from a normal friction material base material for a wet friction material is bonded using an adhesive (thermosetting resin), and both sides are pressed to form islands. A plurality of (40 on one side) oil grooves 9G and 9L are formed with the shaped portions 8F and 8G interposed therebetween.

  As a result, when the ring-type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J according to the first embodiment are incorporated in the AT, they are idle in any direction in the non-fastened state. When the specification is such that the lubricating oil (ATF) is not supplied from the inner peripheral side, the ATF supplied from the outer peripheral side is chamfered parts 8a, 8Aa, 8Ba, 8Ca, 8Da, 8Ea, 8Fa, 8Ga, 8Ha. And the ring-shaped friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, overflowing to the surface of the island-shaped portions 8, 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H Only the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J are smoothly idled in order to secure the space between 6H and 6J and the separator plate.

  Also, in the case of the specification in which lubricating oil (ATF) is supplied from the inner peripheral side, there is a space where ATF flows on the outer periphery of the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, 6J. Since it is sufficient, it is possible to reliably prevent a situation where an oil reservoir is generated on the outer periphery and drag torque is increased.

  Thus, in the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J as the wet friction materials according to the first embodiment, the lubricating oil is supplied from the inner peripheral side. Even when there is no specification (no shaft center lubrication) or when an oil pool is generated on the outer periphery and the stirring torque increases, a greater drag torque reduction effect can be obtained more reliably.

  Further, in the ring type friction materials 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, and 6J as the press type friction material according to the first embodiment, the ring is formed on both surfaces of the flat plate ring-shaped cored bar 2. Since the friction material bases 7 and 10 having a shape are bonded by using an adhesive (thermosetting resin) and both sides are pressed, mass production is easier and cost is reduced. There is an advantage that you can.

  In the first embodiment, only the segment type friction material and the ring type friction material press type friction material are described among the wet friction materials. However, the ring type cutting type friction in which similar oil grooves are formed by cutting. Also in the material, the drag torque reducing effect equivalent to that of the ring type (press type) friction materials 6, 6A, 6C can be obtained.

  In the reference example and the first embodiment, as shown in FIGS. 1, 3, 5, 5, 6, 8, and 11 to 14, the segment pieces 3, 3A, 3B, 3C, 3D are used. , 3E, 3F, 3G, 3H, 3J, 3K, 3L, 3M, 3N or a wet friction material in which a ring-shaped friction material base material 7 or 10 is attached only to a portion offset to the outer peripheral side of the core metal 2 As described above, as shown in Patent Document 1 to Patent Document 4, a segment piece or a ring-shaped friction material base material is pasted with a width of 90% or more of the width from the outer periphery to the inner periphery of the core metal 2. In addition, the drag torque reduction effect similar to that of the reference example and the first embodiment can be obtained.

  In addition, even if a segment piece or a ring-shaped friction material base material is attached with a width of what percentage of the width from the outer periphery to the inner periphery of the cored bar 2, the drag torque is reduced similarly to the reference example and the first embodiment. An effect can be obtained. Furthermore, in the reference example and the first embodiment, the case where the segment piece or the ring-shaped friction material base material is pasted on both surfaces of the core metal 2 has been described. You may affix a segment piece or a ring-shaped friction material base material.

  Furthermore, in the reference example and the first embodiment, when 30 or 40 pieces of segment pieces are attached to one side of the core metal 2 and 30 oil grooves are attached by attaching a ring-shaped friction material base material. Alternatively, only the case where 40 pieces are formed has been described, but the number of segment pieces per one side of the core metal 2 is not limited to 30 or 40, and the number of oil grooves is limited to 30 or 40. You can set as many or as many as you like.

  In carrying out the present invention, the configuration, shape, quantity, material, size, connection relationship, manufacturing method, etc. of other parts of the wet friction material (segment type friction material and ring type friction material) are described in the above reference examples. The present invention is not limited to the first embodiment. In addition, since the numerical value quoted in Embodiment 1 of the present invention does not indicate a critical value but indicates a preferable value suitable for implementation, even if the numerical value is slightly changed, the implementation is denied. It is not a thing.

FIG. 1A is a partial plan view showing a part of a wet friction material (case 1) according to a reference example of the present invention, and FIG. 1B is a wet friction material according to a first modification of the reference example of the present invention ( (C) is a partial plan view showing a part of a wet friction material (case 3) according to a second modification of the reference example of the present invention. FIG. 2A is a partial cross-sectional view showing a longitudinal section of a wet friction material (case 1) according to a reference example of the present invention, and FIG. 2B is a view of a wet friction material according to a third modification of the reference example of the present invention. It is the fragmentary sectional view which showed the longitudinal cross section. FIGS. 3A and 3B are partial plan views showing a part of a wet friction material according to another modification of the reference example of the present invention. 4 (a), (b), (c), (d), (e), and (f) show the shape of a segment piece used in a wet friction material according to another modification of the reference example of the present invention. It is a top view. FIG. 5A is a partial plan view showing a part of a wet friction material according to a fourth modification of the reference example of the present invention, and FIG. 5B is a wet friction material according to the fifth modification of the reference example of the present invention. (C) is a partial plan view showing a part of a wet friction material according to a sixth modification of the reference example of the present invention, and (d) is a partial plan view of the reference example of the present invention. FIG. 7E is a partial plan view showing a part of a wet friction material according to a seventh modification, and FIG. 9E is a partial plan view showing a part of the wet friction material according to an eighth modification of the reference example of the present invention. 6A is a partial plan view showing a part of the wet friction material according to the first example of the prior art (Comparative Example 1), and FIG. 6B is a wet friction material according to the second example of the prior art (Comparative Example) 2) is a partial plan view showing a part of (2), and (c) is a partial plan view showing a part of a wet friction material (Comparative Example 3) according to a third example of the prior art. FIG. 7 shows the relationship between the relative rotational speed and drag torque of the wet friction material (cases 1, 2, 3) according to the reference example of the present invention in comparison with the conventional wet friction material (comparative examples 1, 2, 3). FIG. FIG. 8 is a diagram showing the relationship between parameters in the wet friction material (case 1) according to the reference example of the present invention. FIG. 9 is a graph showing the relationship between the cutting height (radial width) of the outer peripheral corner of the oil groove and the drag torque reduction rate in the wet friction material (case 1) according to the reference example of the present invention. FIG. 10 is a diagram showing the relationship between the cut length (circumferential width) of the outer peripheral corner portion of the oil groove and the drag torque reduction rate in the wet friction material (case 1) according to the reference example of the present invention. FIG. 11A is an explanatory diagram showing the generation of drag torque in a conventional wet friction material (Comparative Example 1), and FIG. 11B is an effect of reducing drag torque in a wet friction material (Case 1) according to a reference example of the present invention. It is explanatory drawing which shows. 12A is a partial plan view showing a part of the wet friction material according to Embodiment 1 of the present invention, and FIG. 12B shows a longitudinal section of the wet friction material according to Embodiment 1 of the present invention. Partial sectional view, (c) is a partial plan view showing a part of a wet friction material according to a first modification of the first embodiment of the present invention, and (d) is a second modification of the first embodiment of the present invention. It is the fragmentary top view which showed a part of wet friction material which concerns on an example. FIG. 13 (a) is a partial sectional view showing a longitudinal section of a wet friction material according to a third modification of the first embodiment of the present invention, and FIG. 13 (b) is a fourth modification of the first embodiment of the present invention. (C) is a partial plan view showing a part of the wet friction material according to the fifth modification of the first embodiment of the present invention. FIG. 14A is a partial plan view showing a part of a wet friction material according to a sixth modification of the first embodiment of the present invention, and FIG. 14B shows a seventh modification of the first embodiment of the present invention. FIG. 8C is a partial plan view showing a part of the wet friction material, and FIG. 8C is a partial plan view showing a part of the wet friction material according to the eighth modification of the first embodiment of the present invention.

1, 1A, 1C, 1D, 1E, 1F, 1G, 1H, 1J, 1K, 1L, 6, 6A, 6C, 6D, 6E, 6F, 6G, 6H, 6J Wet friction material 2 Core metal 3, 3A, 3B , 3C, 3D, 3E, 3F, 3G, 3H, 3I, 3J, 3K, 3L, 3M, 3N Segment piece 3a, 3Aa, 3Ba, 3Ca Notch (chamfering)
3g, 3h, 3i, 3j, 8d Recess 4, 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4J, 4K, 4L, 4M, 9, 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, 9J, 9K, 9L Oil groove 7, 10 Ring-shaped friction material base 8, 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H Island-like portions 8a, 8Aa, 8Ba, 8Ca, 8Da , 8Ea, 8Fa, 8Ga, 8Ha Chamfering

Claims (2)

Ring-type friction in which a ring-shaped friction material base material is bonded to both sides or one side of a flat ring-shaped cored bar and pressed or cut to leave an island-shaped portion to form a plurality of oil grooves in the radial direction A wet friction material,
When the ring-type friction material rotates, drag torque generated by the interaction with the lubricating oil accumulated on the outer periphery of the ring-type friction material is reduced at both corners on the outer periphery side of the island-like portion sandwiched between the plurality of oil grooves. One or both of the parts or the entire outer peripheral side is deleted by R machining or chamfering, and the circumferential length obtained by deleting the outer peripheral side of the island-like part sandwiches the island-like part from which the outer peripheral side is deleted. The wet friction material is characterized in that one or more widths of the outer peripheral opening of the oil groove are provided so as to be four times or more of the narrowest part of the oil groove.   The wet friction material according to claim 1, wherein a concave portion that is recessed with respect to the outer peripheral side is provided in a central portion on the outer peripheral side of the island-shaped portion.

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