JP2009103326A - Manufacturing method for wet friction clutch plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and reliably obtain a depth of H=0.004 mm or more throughout a friction sliding surface. <P>SOLUTION: The manufacturing method for a wet friction clutch plate 1 shaped like a donut disc forms a grid of grooves 11 for holding lubricating oil on a friction sliding surface 9 which comes in contact with a mating clutch plate for frictional engagement, arranged at constant pitches with the friction coefficient of the friction sliding surface 9 as μ and the relative speed by sliding with the mating clutch plate as v, and sets the depth of the grooves 11 within the range from 0.004 to 0.011 mm so that a positive characteristic of μ/v can be obtained, whereby the grid-like grooves 11 for holding lubricating oil are formed on the friction sliding surface 9 having an inner diameter end and an outer diameter end by pressing with a press die having an outer circumference and the depth of the grid-like grooves 11 is set and managed at an intermediate portion between the inner diameter end and outer diameter end of the friction sliding surface 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a wet friction clutch plate in which torque transmission between rotating members is performed by frictional engagement of frictional sliding surfaces.

  As a conventional friction clutch plate of this type, there is one used in a power transmission device described in, for example, JP-A-11-208303.

  The power transmission device is, for example, disposed on a propeller shaft of a four-wheel drive vehicle, and a wet friction clutch plate rotates between an outer rotating member on the propeller shaft side and an inner rotating member on the drive pinion shaft side. It is attached by engaging in the direction. With this wet friction clutch plate subjected to a predetermined pressing force in the axial direction, when a relative rotation occurs between the propeller shaft and the drive pinion shaft, a frictional engagement force can be exerted, and torque can be transmitted between the two. it can.

  The inner and outer rotating members are sealed with a seal to form a space for accommodating the wet friction clutch plate, and the space is filled with lubricating oil. The lubrication oil lubricates the wet friction clutch plates.

  In addition, in order to improve the durability of the wet friction clutch plate, there is a clutch plate in which a lattice-like groove is formed on the friction sliding surface, and lubricating oil is held in the groove, whereby the wet friction clutch plate is provided. The wear of the frictional sliding surface between the clutch plates can be suppressed, and the durability can be improved.

  However, if a grid-like groove is simply formed on the surface of the friction sliding surface of the wet friction clutch plate as described above, the transmission torque becomes unstable during sliding even if the wear can be suppressed, and the torque more than necessary. May occur. For this reason, the strength of the drive system parts must be able to withstand the torque, leading to an increase in size and weight of the drive system parts. There is also a problem that a so-called judder noise is generated when the wet friction clutch plates slide with each other.

  Here, when the friction coefficient of the friction sliding surface of the wet friction clutch plate is μ and the relative speed due to sliding between the wet friction clutch plates is v, the μ-v characteristic increases the relative speed due to sliding. A gradient in which μ increases is generally called “μ-v positive gradient”, and a gradient in which μ decreases is generally called “μ-v negative gradient”. It is known that when this μ-v negative slope is reached, self-excited vibration is generated, and transmission torque is unstable and judder noise is generated.

JP 11-208303 A

  The problem to be solved is to provide a method for manufacturing a wet friction clutch plate that can suppress instability of transmission torque and generation of judder noise.

  According to the present invention, a groove for retaining lubricating oil is formed in a lattice shape on the surface of the friction sliding surface that contacts the mating clutch plate and performs frictional engagement, and the friction coefficient of the friction sliding surface is μ, The relative speed by sliding with the clutch plate is v, the lattice-like grooves are formed at a constant pitch, and the depth of the grooves is 0.004 mm to 0.011 mm so that a positive characteristic of μ / v can be obtained. The method of manufacturing a donut disk-shaped wet friction clutch plate set in the range of the above, wherein the lubricating oil retaining groove is provided on the surface of the friction sliding surface having an inner diameter end and an outer diameter end, and an outer periphery is provided. A grid shape is formed by pressing using a press mold, and the depth of the grid-shaped grooves is set and managed at an intermediate portion between the inner diameter end and the outer diameter end of the friction sliding surface. To do.

  According to the present invention, a groove for retaining lubricating oil is formed in a lattice shape on the surface of the friction sliding surface that contacts the mating clutch plate and performs frictional engagement, and the friction coefficient of the friction sliding surface is μ, The relative speed by sliding with the clutch plate is v, the lattice-like grooves are formed at a constant pitch, and the depth of the grooves is 0.004 mm to 0.011 mm so that a positive characteristic of μ / v can be obtained. The method of manufacturing a donut disk-shaped wet friction clutch plate set in the range of the above, wherein the lubricating oil retaining groove is provided on the surface of the friction sliding surface having an inner diameter end and an outer diameter end, and an outer periphery is provided. A press mold is used to form a grid by pressing, and the depth of the grid-shaped grooves is set and managed at an intermediate portion between the inner diameter end and the outer diameter end of the friction sliding surface.

  For this reason, the manufactured wet friction clutch plate is capable of frictional engagement with the friction sliding surface coming into contact with the mating clutch plate, and holding the lubricating oil in the lattice-shaped grooves formed on the surface. In addition, by performing smooth lubrication with the lubricating oil, wear of the frictional sliding surface can be suppressed and durability can be improved. In addition, the friction coefficient of the friction sliding surface is μ, the relative speed by sliding with the counterpart clutch plate is v, the grid-like grooves are formed at a constant pitch, and the depth of the grooves is μ / v. Since it is set in the range of 0.004 mm to 0.011 mm so as to obtain a positive characteristic, it is possible to suppress the destabilization of the transmission torque when the friction sliding surface slides and to suppress the generation of so-called judder noise. be able to.

  Further, even when the groove for retaining the lubricating oil is formed on the surface of the friction sliding surface having the inner diameter end and the outer diameter end by a press using a press die having an outer periphery, the friction sliding surface is used. A depth of H = 0.004 mm or more can be easily and reliably obtained over the entire moving surface.

It is a front view of the wet friction clutch board concerning one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the arrow SA-SA in FIG. 1 according to the embodiment. It is an important section enlarged view of the surface of a friction sliding surface concerning one embodiment. FIG. 4 is a sectional view taken along the line SB-SB in FIG. 3 according to the embodiment. It is a graph which concerns on one Embodiment and shows a μ-v characteristic. It is a graph which concerns on a comparative example and shows a μ-v characteristic.

  1 to 4 relate to an embodiment of the present invention, FIG. 1 is a front view of a wet friction clutch plate, FIG. 2 is a sectional view taken along the arrow SA-SA in FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view taken along arrow SB-SB in FIG.

  As shown in FIGS. 1 and 2, the wet friction clutch plate 1 has a donut disk shape, and is formed of, for example, carbon tool steel (SK5) or the like, and is subjected to a predetermined surface treatment. The wet friction clutch plate 1 has an inner diameter of about 48 mm, an outer diameter of about 82 mm, and a thickness t = 0.8 mm. However, these dimensions are examples and can be arbitrarily selected.

  The outer peripheral surface 3 is formed in a circular shape, and a tooth portion 5 that is spline-fitted to, for example, a male spline on the rotating member side is provided on the inner peripheral surface. A plurality of windows 7 are provided at a predetermined pitch in the circumferential direction at an intermediate portion between the inner and outer periphery of the wet friction clutch plate 1. In the present embodiment, six windows 7 are provided in an arc shape. When the wet friction clutch plate 1 is configured as an electromagnetic clutch, for example, as in the conventional power transmission device, the window 7 forms an air gap by the window 7 and ensures that magnetic lines of force are generated between the electromagnetic coil and the armature. It is for making it form.

  On the surface of the friction sliding surface 9 of the wet friction clutch plate 1, grooves 11 for retaining lubricating oil are formed in a lattice shape. As shown in FIG. 3, the lattice-like grooves 11 are formed by a plurality of parallel groove portions 13 and a plurality of parallel groove portions 15 orthogonal to the groove portions 13. A portion 17 surrounded by the groove portions 13 and 15 has a square shape, and four corners 19 of each portion 17 are formed with rounded corners, and an intersection portion 21 of the groove portions 13 and 15 is slightly larger than the width of the groove portions 13 and 15. It has become a form. Therefore, the lubricating oil can be easily stored in the intersection 21.

  The groove portions 13 and 15 are formed in the same width, depth, and pitch, and the groove portion 13 is illustrated in FIG. That is, the grooves 13 are formed at a constant pitch P, and in this embodiment, are formed at a fine pitch of about P = 0.3 mm. The width B of the groove 13 is formed to be about B = 0.04 mm, and the bottom is formed in a round shape.

  The depth H of the groove 13 is formed to be H = 0.004 mm in this embodiment. However, the depth H of the groove 13 can be formed to be H = 0.004 mm or more. That is, the lattice-shaped grooves 11 are formed at a constant pitch P, and the groove depth is set to 0.004 mm or more.

  Further, in the present embodiment, the lattice-shaped grooves 11 are formed on the surface of the friction sliding surface 9 by press working, and the depth H of the grooves 11 is H = 0.004 mm at the intermediate portion of the friction sliding surface 9. It is set to. Here, the intermediate portion of the frictional sliding surface 9 is a range surrounded by an alternate long and short dash line as shown in FIG. 1, that is, between the inner diameter end on the tooth portion 5 side and the outer diameter end on the outer peripheral surface 3 side. . In general, when the groove 11 is pressed, the intermediate portion between the inner diameter end and the outer diameter end of the friction sliding surface 9 is less likely to escape the meat than the inner and outer diameter ends. This is because the depth tends to become shallower, and the depth H of the groove 11 is set and managed at 0.004 mm or more at the shallower part.

  Further, in the intermediate portion, the outer peripheral side is pulled by the press work, and the inner peripheral side is compressed, so that the meat is difficult to escape on the inner peripheral side, the influence of the deflection on the outer peripheral side of the press die, etc. In particular, the groove depth tends to be the shallowest in the range of the hatched portion F on the inner diameter side, surrounded by the one-dot chain line in FIG. For this reason, by setting H = 0.004 mm within the range of the hatched portion F, it is possible to set H = 0.004 mm or more in any part of the entire groove 11. By controlling the depth of the groove 11 as described above, it is possible to easily and reliably obtain a depth of H = 0.004 mm or more on the entire friction sliding surface 9.

  The depth H of the groove 11 can be made uniform over the entire friction sliding surface 9. That is, it is possible to make the depth H of the groove 11 uniform over the entire friction sliding surface 9 by using a shallow groove press on both the inner peripheral side and the outer peripheral side. Management can be performed at any position on the inner and outer peripheral sides of the frictional sliding surface 9.

  By using the wet friction clutch plate 1 as described above, the friction sliding surface 9 can be brought into contact with the counterpart clutch plate to perform frictional engagement, and torque can be transmitted between the rotating members that rotate relative to each other. In this case, as the mating clutch plate, a flat clutch plate, a friction sliding surface with radiation grooves, concentric circular grooves, spiral grooves, etc. arranged in parallel at regular intervals, a so-called sunburst groove, etc. are used. . However, the type of the counterpart clutch plate is not particularly limited.

  Lubricating oil can be held in the groove 11 during such torque transmission to suppress wear of the wet friction clutch plate 1 and improve durability. Moreover, by forming the grooves 11 at a constant pitch P and setting the depth of the grooves 11 to be H = 0.004 mm or more, the instability of the transmission torque during sliding of the friction sliding surface is suppressed, and Generation of so-called judder noise can be suppressed.

  5 and 6 are graphs showing μ-v characteristics, FIG. 5 is a graph of μ-v characteristics according to an embodiment of the present invention, and FIG. 6 is a graph of μ-v characteristics according to a comparative example. 5 and 6, the horizontal axis indicates the change in differential rotation (rpm) between the wet friction clutch plates that are frictionally engaged, and the vertical axis indicates the change in the friction coefficient μ of the friction sliding surface.

  As an experimental condition, in the case of FIG. 5, the depth H of the groove 11 was selected in the range of 0.004 mm to 0.011 mm, and the experiment was performed. In the case of FIG. 6, the experiment was conducted by selecting the depth of the groove 11 in the range of 0.001 mm or more and less than 0.004 mm.

  As a result, in the case of the present embodiment selected in the range of the groove depth H = 0.004 mm or more and 0.011 mm or less, all show a tendency as shown in FIG. 5 and the friction coefficient μ in accordance with the increase in the differential rotation. Showed a positive μ-v slope characteristic. On the other hand, when the groove depth H is selected in the range of 0.001 mm or more and less than 0.004 mm, both show the tendency as shown in FIG. 6, and the friction at two places is high when the differential rotation is low and high. The characteristic of the μ-v negative gradient in which the coefficient μ decreases is shown.

  As a result, when the groove depth H = 0.001 mm or more and less than 0.004 mm is selected as shown in FIG. 6, self-excited vibration is generated during sliding, and the transmission torque becomes unstable or so-called judder noise is generated. However, when the groove depth H is 0.004 mm or more as in the embodiment of the present invention, the occurrence of self-excited vibration is suppressed by the characteristic of the μ-v positive gradient, and the transmission torque is reduced. Instability and judder noise can be suppressed.

  In the above embodiment, the groove depth H = 0.004 mm. However, as is clear from the experimental results, it is preferable to select the groove depth in the range of H = 0.004 mm to 0.011 mm. Further, for the pitch P and the groove width B of the grooves 11, it is preferable to select the ranges of P = 0.2 to 0.9 mm, B = 0.02 to 0.1 mm, and the plate thickness t = 0.7 to It is preferable to select in the range of 1.0 mm.

1 Wet friction clutch plate 9 Friction sliding surface 11 Groove H Groove depth

Claims (3)

Grooves for retaining lubricating oil are formed in a lattice shape on the surface of the friction sliding surface that makes frictional engagement by contacting the mating clutch plate,
The friction coefficient of the friction sliding surface is μ, the relative speed by sliding with the counterpart clutch plate is v,
A donut disk-shaped wet friction clutch plate in which the lattice-shaped grooves are formed at a constant pitch, and the depth of the grooves is set in a range of 0.004 mm to 0.011 mm so as to obtain a positive characteristic of μ / v. A manufacturing method of
On the surface of the friction sliding surface provided with an inner diameter end and an outer diameter end, the groove for retaining the lubricating oil is formed in a grid shape by pressing using a press die having an outer periphery,
The depth of the lattice-like grooves is set and managed in an intermediate portion between the inner diameter end and the outer diameter end of the friction sliding surface.
A method of manufacturing a wet friction clutch plate characterized by the above. A method of manufacturing a wet friction clutch plate according to claim 1,
In the wet friction clutch plate, a plurality of windows are formed at a predetermined pitch in the circumferential direction in an intermediate portion between the inner and outer periphery,
The setting management of the depth of the grid-like grooves by the press is performed on the inner diameter side from the plurality of windows,
A method of manufacturing a wet friction clutch plate characterized by the above. It is a manufacturing method of the wet friction clutch board according to claim 1 or 2,
The lattice-shaped grooves were set to a depth of 0.004 mm or more at the intermediate portion of the friction sliding surface.
A method of manufacturing a wet friction clutch plate characterized by the above.

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