JP2006250364A - Driving force transmission device - Google Patents

Abstract

The present invention provides a durable clutch plate that is less likely to wear, a friction clutch including the clutch plate, and a driving force transmission device.
A diamond-like carbon thin film D is applied to a sliding surface S2 of an outer clutch plate 34b by a known method such as a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or an ion deposition method. And the friction clutch 34 which comprised the outer clutch plate 34b and the inner clutch plate 34a so that frictional engagement was possible is comprised. Further, the friction clutch 34 is employed in the driving force transmission device.
[Selection] Figure 3

Description

  The present invention relates to a driving force transmission device in which wear hardly occurs.

2. Description of the Related Art Conventionally, a friction clutch that transmits power by frictionally engaging a driving side clutch plate and a driven side clutch plate is known.
The sliding surfaces of both clutch plates in the friction clutch are subjected to a surface treatment in order to suppress wear due to frictional engagement. As an example of the surface treatment, there is one in which the composition of the sliding surfaces of both clutch plates is changed by nitriding treatment or quenching and tempering treatment. In this way, wear is reduced by strengthening the sliding surfaces of both clutch plates.

  However, even if the friction clutch is subjected to the above-described treatment, the durability is poor when dry friction engagement is performed or when friction engagement is performed with a large force even in the friction engagement in the lubricating oil.

  Therefore, the present invention has been made in view of the above-described circumstances, and an object thereof is to provide a durable driving force transmission device that is less likely to wear.

  In order to achieve the above object, the invention described in claim 1 is a drive which is arranged between rotating members positioned so as to be relatively rotatable with each other, and transmits a driving force between these rotating members by frictional engagement. The gist of the present invention is a force transmission device in which a diamond-like carbon thin film having an amorphous structure is applied to one of sliding surfaces that are frictionally engaged.

The gist of the invention according to claim 2 is that, in the driving force transmission device according to claim 1, lubricating oil is interposed between the sliding surfaces, and wet friction engagement is performed.
The gist of the invention described in claim 3 is that in the driving force transmission device according to claim 1 or 2, the other of the sliding surfaces is subjected to nitriding treatment or quenching tempering treatment. .

  According to a fourth aspect of the present invention, in the driving force transmission device according to any one of the first to third aspects, the other of the sliding surfaces includes a plurality of circumferentially extending directions. The gist is that a groove having a fine width is formed.

  According to a fifth aspect of the present invention, in the driving force transmission device according to any one of the second to fourth aspects, a substantially mesh-shaped groove is formed on the one sliding surface. This is the gist.

  The gist of a sixth aspect of the present invention is that the driving force transmission device according to any one of the first to fifth aspects transmits a driving force of a vehicle.

  As described in detail above, according to the first to sixth aspects of the invention, wear hardly occurs and durability is improved.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a driving force transmission device according to an embodiment of the present invention. As shown in FIG. 2, the driving force transmission device 11 is disposed in a driving force transmission path to the rear wheel side in the four-wheel drive vehicle 12.

The four-wheel drive vehicle 12 includes a driving force transmission device 11, a transaxle 13, an engine 14, a pair of front wheels 15, and a pair of rear wheels 16.
The driving force of the engine 14 is output to the axle shaft 17 via the transaxle 13 to drive the front wheels 15.

  A driving force transmission device 11 is connected to the transaxle 13 via a propeller shaft 18, and a rear differential 20 is connected to the driving force transmission device 11 via a drive pinion shaft 19. A rear wheel 16 is connected to the rear differential 20 via an axle shaft 21. When the propeller shaft 18 and the drive pinion shaft 19 are connected by the driving force transmission device 11 so that torque can be transmitted, the driving force of the engine 14 is transmitted to the rear wheel 16.

  The driving force transmission device 11 is accommodated in the differential carrier 22 together with the rear differential 20, supported by the differential carrier 22, and supported by the vehicle body via the differential carrier 22.

Next, the driving force transmission device 11 will be described.
As shown in FIG. 1, the driving force transmission device 11 includes an outer case 30a as an outer rotating member, an inner shaft 30b as an inner rotating member, a main clutch mechanism 30c, a pilot clutch mechanism 30d, and a cam mechanism 30e.

The main clutch mechanism 30c corresponds to the clutch portion and the main clutch of the present invention.
The outer case 30a includes a bottomed cylindrical front housing 31a and a rear housing 31b that is screwed into a rear end opening of the front housing 31a and covers the opening. An input shaft 50 projects from the front end portion of the front housing 31a, and the input shaft 50 is connected to the propeller shaft 18 (see FIG. 2).

  The front housing 31a is made of aluminum, which is a nonmagnetic material, and the rear housing 31b is made of iron, which is a magnetic material. A stainless steel cylinder 51, which is a nonmagnetic material, is embedded in the radial intermediate portion of the rear housing 31b. The cylinder 51 forms an annular nonmagnetic portion.

  The outer case 30a is rotatably supported on the outer periphery of the front end portion of the front housing 31a with respect to the differential carrier 22 (see FIG. 2) via a bearing (not shown). The outer case 30a is supported on the outer periphery of the rear housing 31b by a yoke 36 that is supported by the differential carrier 22 (see FIG. 2) via a bearing or the like.

  The inner shaft 30b penetrates the central portion of the rear housing 31b in a liquid-tight manner and is inserted into the front housing 31a. The inner shaft 30b is relative to the front housing 31a and the rear housing 31b in a state where movement in the axial direction is restricted. It is rotatably supported. The tip of the drive pinion shaft 19 (see FIG. 2) is inserted and connected to the inner shaft 30b. In FIG. 1, the drive pinion shaft 19 is not shown.

  As shown in FIG. 1, the main clutch mechanism 30c is a wet multi-plate type clutch mechanism, and includes a large number of iron inner clutch plates 32a and iron outer clutch plates 32b. A paper-type wet friction material is attached to the sliding surfaces on both sides of the clutch plate 32a. For this reason, when the clutch plates 32a and 32b are engaged with each other, the raw materials (irons) are not in direct sliding contact with each other, and as a result, iron wear particles are hardly generated.

  The inner clutch plate 32a and the outer clutch plate 32b are disposed on the back wall side of the front housing 31a. Each inner clutch plate 32a is spline-fitted to the outer periphery of the inner shaft 30b and assembled so as to be movable in the axial direction.

  On the other hand, each outer clutch plate 32b is spline-fitted to the inner periphery of the front housing 31a and assembled so as to be movable in the axial direction. The inner clutch plates 32a and the outer clutch plates 32b are alternately positioned so as to come into contact with each other and frictionally engage with each other, and are separated from each other to be in an unengaged free state.

  The pilot clutch mechanism 30d includes an electromagnet 33, a friction clutch 34 as a clutch portion, and an armature 35. The electromagnet 33 and the armature 35 constitute an electromagnetic drive means.

  As shown in FIG. 1, the yoke 36 is supported by an inlay with respect to the differential carrier 22 (see FIG. 2), and is supported so as to be rotatable relative to the outer periphery of the rear end portion of the rear housing 31b. An annular electromagnet 33 is fitted on the yoke 36, and the electromagnet 33 is fitted in an annular recess 53 of the rear housing 31b.

The friction clutch 34 is configured as a multi-plate friction clutch including a plurality of iron inner clutch plates 34a and a plurality of iron outer clutch plates 34b.
The inner clutch plate 34a corresponds to “the other clutch plate”, and the outer clutch plate 34b corresponds to “one clutch plate”.

  The inner clutch plate 34a is spline-fitted to the outer periphery of a first cam member 37 constituting a cam mechanism 30e described later, and is assembled so as to be movable in the axial direction. On the other hand, each outer clutch plate 34b is spline-fitted to the inner periphery of the front housing 31a and assembled so as to be movable in the axial direction.

  The inner clutch plates 34a and the outer clutch plates 34b are alternately positioned so that both a friction engagement state where they are in contact with each other and a free state where they are separated from each other and disengaged are possible.

As shown in FIG. 3, the inner clutch plate 34a and the outer clutch plate 34b are formed with sliding surfaces S1 and S2 that come into contact with each other.
As shown in FIGS. 3 and 4, on the entire sliding surface S1 of the clutch plate 34a, a large number of grooves 40 having a small width are provided in parallel with a small interval by pressing. The sliding surface S1 is subjected to a known nitriding process or a known quenching and tempering process. The groove 40 is exaggerated for easy understanding, but it is sufficient that the groove pitch and height are formed in units of μm.

  As shown in FIG. 3, a diamond-like carbon thin film D is applied to the sliding surface S2 by a known method such as a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or an ion deposition method. Yes.

That is, for example, the diamond-like carbon thin film D is formed on the outer clutch plate 34b by the following apparatus.
An apparatus 61 shown in FIG. 8 is for performing high-temperature plasma CVD and includes a vacuum chamber 63 having an exhaust port 62. In the vacuum chamber 63, a cathode 64 and an anode 65 for discharging are provided. A power source 66 is connected to the cathode 64 and the anode 65, and a DC voltage is applied to the cathode 64 and the anode 65 by the power source 66. A supply port 67 is formed at the tip of the anode 65.

  A raw material gas for synthesizing the diamond-like carbon thin film D passes between the cathode 64 and the anode 65 as shown by an arrow in the figure, and is supplied into the vacuum chamber 63 through the supply port 67. And the plasma decomposed | disassembled and excited by the electric discharge in the vicinity of the supply port 67 is produced | generated. In the series of operations from the plasma generation to the diamond-like carbon thin film D forming, the inside of the vacuum chamber 63 is at a low pressure. A holder 68 is disposed in the vacuum chamber 63, and the outer clutch plate 34 b is set in the holder 68.

  Then, the generated plasma is applied to the sliding surface S2 of the outer clutch plate 34b set on the holder 68 to grow the diamond-like carbon thin film D on the sliding surface S2. In this way, the diamond-like carbon thin film D is deposited until an appropriate thickness is obtained. In the present embodiment, the diamond-like carbon thin film D has a thickness of 3 μm.

  By making the film thickness of the diamond-like carbon thin film D in the range of 0.1 to 10 μm, the protection of the sliding surface S2 can be realized, but the film thickness is preferably in the range of 1 to 5 μm. If the thickness is less than 0.1 μm, the durability life against wear is short and it is not suitable for practical use. Conversely, if it exceeds 10 μm, the film becomes brittle. Diamond-like carbon is called DLC.

  By the way, as shown in FIG. 1, the armature 35 has an annular shape, and is assembled by being spline-fitted to the inner periphery of the front housing 31a so as to be movable in the axial direction. The armature 35 is located on one side of the friction clutch 34 and faces the friction clutch 34.

  By energizing the electromagnetic coil of the electromagnet 33, a magnetic path L1 that circulates between the yoke 36, the rear housing 31b, the first cam member 37, the armature 35, the friction clutch 34, the rear housing 31b, and the yoke 36 is formed.

  As shown in FIG. 1, the cam mechanism 30 e includes a first cam member 37, a second cam member 38, and a cam follower 39. The first cam member 37 and the second cam member 38 are formed in a substantially disk shape.

  In the first cam member 37 and the second cam member 38, a plurality of cam grooves (not shown) facing each other are formed on the opposing surfaces at a predetermined interval in the circumferential direction. The first cam member 37 is rotatably fitted to the outer periphery of the inner shaft 30b and is rotatably supported via the thrust bearing 41 with respect to the rear housing 31b. On the outer periphery of the first cam member 37, the inner clutch plate 34a is spline-fitted to a portion near the rear housing 31b so as to be movable in the axial direction. On the other hand, on the outer periphery of the first cam member 37, the portion on the main clutch mechanism 30 c side is in contact with the inner peripheral surface of the armature 35 so as to be relatively rotatable.

  As shown in FIG. 5, a seal ring receiving groove 42a is formed on the inner peripheral surface of the first cam member 37 in which the inner shaft 30b is fitted. A seal ring 42b is stored in the seal ring storage groove 42a. The inner ring 30b and the first cam member 37 are in a liquid-tight state by the seal ring 42b.

  Further, a sealing ring receiving groove 43a is formed on the inner peripheral surface of the armature 35. A seal ring 43b is stored in the seal ring storage groove 43a. The first cam member 37 and the armature 35 are in a liquid-tight state by the seal ring 43b.

  Similarly, on the outer peripheral surface of the armature 35, a sealing ring housing groove 44a is formed. A seal ring 44b is stored in the seal ring storage groove 44a. The armature 35 and the front housing 31a are liquid-tight by the seal ring 44b.

  The armature 35, the first cam member 37, and the seal rings 42b, 43b, and 44b constitute a seal mechanism I. The seal rings 42b, 43b, 44b correspond to seal members.

  As shown in FIG. 1, in this embodiment, a space surrounded by the front housing 31a, the armature 35, the first cam member 37, and the inner shaft 30b is defined as a storage chamber K1. A space surrounded by the inner shaft 30b, the first cam member 37, the armature 35, the front housing 31a, and the rear housing 31b is defined as a storage chamber K2.

  The second cam member 38 is spline-fitted to the outer periphery of the inner shaft 30b so as to be movable in the axial direction, and is assembled to the inner shaft 30b so as to be integrally rotatable. The second cam member 38 is positioned to face the inner clutch plate 32a of the main clutch mechanism 30c. A ball-shaped cam follower 39 is interposed in the cam grooves of the second cam member 38 and the first cam member 37 facing each other.

  As a result, the armature 35 is located on one side of the friction clutch 34 inside the front housing 31a, and the electromagnet 33 is located on the other side of the friction clutch 34 with the rear housing 31b sandwiched on the opening side of the front housing 31a. The housing 31b functions as a magnetic path forming member.

  The rear housing 31b is screwed to the front housing 31a at the peripheral edge portion of the wall portion thereof in a state of being fluid-tightly and rotatably fitted to the outer periphery of the inner shaft 30b. The rear housing 31b is supported in a liquid-tight and rotatable manner on the differential carrier 22 (see FIG. 2) via an oil seal (not shown) on the outer periphery of the rear end portion of the rear cylinder portion.

  The storage chamber K1 is filled with lubricating oil, and the lubricating oil lubricates both the clutch plates 32a and 32b. In this embodiment, the lubricating oil is filled in the storage chamber K1 by about 80% by volume. The lubricating oil in the storage chamber K1 cannot be leaked to the storage chamber K2 by the seal mechanism I. The storage chamber K1 corresponds to a lubricating oil filling space, and the storage chamber K2 corresponds to an unfilled lubricating oil space. The thrust bearing 41 in the storage chamber K2 is lubricated with grease.

  In the driving force transmission device 11 as described above, when the electromagnetic coil of the electromagnet 33 constituting the pilot clutch mechanism 30d is not energized, the magnetic path L1 is not formed, and the friction clutch 34 is in the disengaged state. It is in. Therefore, the pilot clutch mechanism 30d is in an inoperative state, and the first cam member 37 constituting the cam mechanism 30e can rotate integrally with the second cam member 38 via the cam follower 39, and the main clutch mechanism 30c. Is inactive. For this reason, the four-wheel drive vehicle 12 constitutes a two-wheel drive mode.

  On the other hand, when the electromagnetic coil of the electromagnet 33 is energized, a magnetic path L1 is formed in the pilot clutch mechanism 30d, and the electromagnet 33 attracts the armature 35. Therefore, the armature 35 presses and frictionally engages the friction clutch 34, connects the first cam member 37 of the cam mechanism 30e to the front housing 31a side, and causes relative rotation with the second cam member 38. . As a result, in the cam mechanism 30e, the cam follower 39 presses both the cam members 37 and 38 away from each other.

  As a result, the second cam member 38 is pressed toward the main clutch mechanism 30c, causing the main clutch mechanism 30c to frictionally engage according to the friction engagement force of the friction clutch 34, and the torque between the outer case 30a and the inner shaft 30b. Make a transmission. Therefore, the four-wheel drive vehicle 12 constitutes a four-wheel drive drive mode in which the propeller shaft 18 and the drive pinion shaft 19 are not directly connected.

  Further, when the current applied to the electromagnetic coil of the electromagnet 33 is increased to a predetermined value, the attractive force of the electromagnet 33 to the armature 35 increases. The armature 35 is strongly attracted to the electromagnet 33 side to increase the friction engagement force of the friction clutch 34 and increase the relative rotation between the cam members 37 and 38. As a result, the cam follower 39 increases the pressing force with respect to the second cam member 38 to bring the main clutch mechanism 30c into the coupled state. For this reason, the four-wheel drive vehicle 12 constitutes a four-wheel drive drive mode in which the propeller shaft 18 and the drive pinion shaft 19 are directly connected.

Next, the characteristic operation of the driving force transmission device 11 will be described.
The conventional drive transmission device described below is the same as the drive force transmission device 11 of the present embodiment, in which the seal rings 42b, 43b, and 44b are omitted, and the storage chamber K1 and the storage chamber K2 are communicated with each other. It is assumed that the room can be moved freely. In the conventional drive transmission device, both the storage chambers K1 and K2 (the space surrounded by the outer case and the inner shaft) are filled with about 80% by volume of the lubricant in the storage chamber. Further, it is assumed that the outer clutch plate in the friction clutch of the conventional drive transmission device is not subjected to the diamond-like carbon thin film D on the sliding surface and is subjected to nitriding treatment. Therefore, the friction clutch is configured to perform frictional engagement in a state where the lubricating oil is supplied.

For comparison, the torque transmission capability of the conventional driving force transmission device is the same as that of the driving force transmission device of this embodiment.
FIG. 6 is a graph showing the relationship between the rotational speed of the inner shaft (corresponding to the inner shaft 30b) and the drag torque in the conventional driving force transmission device. FIG. 6 shows experimental results in which the outer case (corresponding to the outer case 30a) is fixed and the inner shaft is rotated.

  This graph shows the drag torque transmitted from the inner shaft to the outer case due to the viscosity of the hydraulic oil and the residual magnetism when the electromagnetic coil of the electromagnet (corresponding to the electromagnet 33) is not energized. In addition, FIG. 6 is performed at -20 degree | times (degrees Centigrade).

Line a is a drag torque generated by the influence of the viscosity of the lubricating oil on the main clutch (corresponding to the main clutch mechanism 30c).
Line b represents drag torque generated by the residual magnetism of the electromagnet affecting the friction clutch (corresponding to the friction clutch 34) in addition to the drag torque of the main clutch.

  Line c is the drag torque generated by the influence of the viscosity of the lubricating oil on the friction clutch in addition to the drag torque of the main clutch and the drag torque due to residual magnetism with respect to the friction clutch.

  Accordingly, in FIG. 6, when the inner shaft speed is 200 min-1, about 14% of the drag torque is derived from the viscosity of the lubricating oil with respect to the main clutch (hereinafter, this drag torque is referred to as A torque). . Further, when the rotational speed is 200 min-1, about 4% of the drag torque is derived from the residual magnetism of the electromagnet with respect to the friction clutch (hereinafter, this drag torque is referred to as B torque). Similarly, when the rotational speed is 200 min-1, about 82% of the drag torque is derived from the viscosity of the lubricating oil with respect to the friction clutch (hereinafter, this drag torque is referred to as C torque).

As a result, the C torque is larger than the A torque and the B torque.
The reason why the C torque becomes the largest is that when the viscosity of the lubricating oil affects the friction clutch, the influence is amplified by the cam mechanism (corresponding to the cam mechanism 30e) when transmitted to the main clutch side. It is.

On the other hand, in the driving force transmission device 11 of the present embodiment, the friction torque is not supplied to the friction clutch 34, so that the C torque is not generated.
Therefore, as shown in FIG. 7, when the rotational speed of the inner shaft is set to 200 min−1 under the condition of −20 degrees (degrees Celsius), the driving force transmission device 11 is compared with the conventional driving force transmission device. The drag torque is reduced by about 82%.

  By the way, since the sliding surfaces of both clutch plates of the conventional driving force transmission device are subjected to nitriding treatment or quenching and tempering treatment, if both clutch plates are engaged by dry friction, the wear is severe. However, since the friction clutch 34 of the present embodiment is provided with the diamond-like carbon thin film D on the sliding surface S2 of the outer clutch plate 34b, it is difficult to cause wear. Moreover, since the diamond-like carbon thin film D is a kind of carbon film, it also serves as a solid lubricant. Therefore, when the diamond-like carbon thin film D is applied to the sliding surface S2, the sliding surface S1 of the inner clutch plate 34a that is in sliding contact with the sliding surface S2 is not easily worn. Therefore, by applying the diamond-like carbon thin film D to the sliding surface S2, both the clutch plates 34a and 34b can be improved in durability. In addition, the durability of the friction clutch 34 itself and the driving force transmission device 11 itself is improved.

  Further, in the conventional driving force transmission device, the wear particles generated in the friction clutch are mixed into the lubricating oil, whereas in the driving force transmission device 11, the wear particles generated in the friction clutch 34 are transferred to the lubricating oil in the storage chamber K1. Do not mix.

Therefore, it can be seen that the driving force transmission device 11 of the present embodiment has a significantly reduced drag torque and an excellent durability life compared to the conventional driving force transmission device.
Therefore, according to the driving force transmission device 11 of the present embodiment, the following effects can be obtained.

  (1) In this embodiment, the friction clutch 34 includes both clutch plates 34a and 34b, and the diamond-like carbon thin film D is applied to the sliding surface S2 of the clutch plate 34b. Therefore, by applying the diamond-like carbon thin film D to the sliding surface S2, both the clutch plates 34a and 34b can be improved in durability. In addition, the durability of the friction clutch 34 itself and the driving force transmission device 11 itself is improved.

  (2) In this embodiment, the main clutch mechanism 30c and the friction clutch 34 are provided, and the storage chamber K1 for storing the main clutch mechanism 30c and the storage chamber K2 for storing the friction clutch 34 are sealed with each other. The friction clutch 34 is configured to be freely connected and disconnected by the operation of the electromagnet 33 and the armature 35 (electromagnetic drive means). The storage chamber K1 was filled with lubricating oil, and the storage chamber K2 was not filled with lubricating oil. Then, the friction clutch 34 is engaged by dry friction.

  Therefore, the C torque shown in FIG. 6 (the drag torque caused by the lubricating oil) is not generated in the driving force transmission device 11. Therefore, since the friction clutch 34 is not affected by the viscosity of the lubricating oil, the driving force transmission device 11 can suppress the drag torque. In addition, by sealing the storage chamber K1 and the storage chamber K2 from each other, it is possible to prevent the lubricating oil in the storage chamber K1 from leaking into the storage chamber K2.

  On the other hand, in the conventional driving force transmission device, since the friction clutch is configured to perform frictional engagement using lubricating oil, the viscosity of the lubricating oil is maintained even when the electromagnet's electromagnetic coil is not energized. Shear friction may cause the friction clutch to be slightly frictionally engaged. As a result, the rotation of the outer case is transmitted to the inner shaft even though the electromagnetic coil of the electromagnet is not energized, and drag torque may be generated. Especially at low temperatures, the viscosity of the lubricating oil increases and drag torque is likely to occur.

  (3) In the present embodiment, the friction clutch 34 that performs dry friction engagement is disposed between the outer case 30a and the inner shaft 30b that are relatively rotatable with respect to each other. The friction clutch 34 is frictionally engaged by the electromagnet 33 and the armature 35 (electromagnetic drive means). The outer case 30a and the inner shaft 30b include a main clutch mechanism 30c that is located between the two members and transmits torque between the outer case 30a and the inner shaft 30b by friction engagement.

  The friction clutch 34, the electromagnet 33 and the armature 35 constitute a pilot clutch mechanism 30d. A cam mechanism 30e is provided that transmits the frictional engagement force of the pilot clutch mechanism 30d to the main clutch mechanism 30c and frictionally engages the main clutch mechanism 30c. Therefore, the driving force transmission device 11 including the outer case 30a, the inner shaft 30b, the main clutch mechanism 30c, the pilot clutch mechanism 30d, and the cam mechanism 30e can accurately perform the friction engagement and the release of the friction clutch 34. .

  (4) In this embodiment, the electromagnetic driving means is constituted by the armature 35 and the electromagnet 33. The friction clutch 34 is frictionally engaged by the armature 35 and the electromagnet 33. Accordingly, the friction clutch 34 can be freely connected and disconnected by the armature 35 and the electromagnet 33.

  (5) In the present embodiment, the seal mechanism I is configured by the armature 35, the first cam member 37, and the seal rings 42b, 43b, and 44b. The storage chamber K1 and the storage chamber K2 are sealed with each other by the sealing mechanism I.

  Accordingly, the lubricant in the storage chamber K1 cannot be leaked into the storage chamber K2 by the armature 35, the first cam member 37, and the seal rings 42b, 43b, and 44b. Further, in terms of the number of parts, it is possible to prevent the lubricating oil from leaking into the storage chamber K2 while only increasing the seal rings 42b, 43b, 44b as compared with the conventional driving force transmission device. Therefore, it is possible to prevent the lubricating oil from leaking into the storage chamber K2 without increasing the number of parts so much.

  (6) In the present embodiment, the main clutch mechanism 30c is disposed in the storage chamber K1, and the friction clutch 34 is disposed in the storage chamber K2. And the sealing mechanism I prevented the lubricating oil in the storage chamber K1 from entering the storage chamber K2. Therefore, even if wear particles are generated in the friction clutch 34, the wear particles are blocked by the seal mechanism I and do not leak into the lubricating oil in the storage chamber K1. As a result, the durability life of the driving force transmission device 11 can be improved.

  (7) In the present embodiment, a known nitriding process or a known quenching process is performed on the sliding surface S1 of the inner clutch plate 34a. Therefore, the inner clutch plate 34a is more durable than a clutch plate in which the sliding surface is not subjected to a known nitriding treatment or a known quenching treatment.

(8) In this embodiment, a plurality of grooves 40 having a minute width are provided along the circumferential direction with respect to the sliding surface S1 of the inner clutch plate 34a. Accordingly, the contact area between the inner clutch plate 34a and the outer clutch plate 34b can be set to an arbitrary area.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.

  In addition, each member and mechanism which comprise the driving force transmission apparatus 111 of 2nd Embodiment are a structure substantially the same as each member and mechanism which comprise the driving force transmission apparatus 11 of the said 1st Embodiment, and substantially the same. There is something that plays a function. Accordingly, among the members and mechanisms constituting the driving force transmission device 111 of the second embodiment, the members and mechanisms constituting the driving force transmission device 11 of the first embodiment exhibit substantially the same configurations and functions. About, the numerical value of the code | symbol of each member and mechanism of 1st Embodiment is added, the detailed description is abbreviate | omitted, and only a different part is demonstrated.

  The driving force transmission device 11 of the first embodiment has the storage chamber K1 and the storage chamber K2 formed therein by the seal mechanism I. The main clutch mechanism 30c in the storage chamber K1 is configured to be wet frictionally engaged, and the friction clutch 34 in the storage chamber K2 is configured to be dry frictionally engaged.

However, in this embodiment, as shown in FIG. 9, both the main clutch mechanism 130c and the friction clutch 134 are configured to be wet frictionally engaged.
Therefore, in this embodiment, the seal ring storage grooves 42a, 43a, 44a and the seal rings 42b, 43b, 44b constituting the seal mechanism I are omitted. In the present embodiment, the concept of the storage room K1 and the storage room K2 is also eliminated.

  Further, the outer peripheral surface of the first cam member 137 is slightly separated from the inner peripheral surface of the armature 135. A storage chamber formed by being surrounded by the outer case 130a, the inner shaft 130b, and the rear housing 131b is filled with lubricating oil. The lubricating oil is configured to lubricate both clutch plates 132a and 132b and to lubricate both clutch plates 134a and 134b.

  In this embodiment, the friction clutch 134 is configured as a multi-plate friction clutch including one inner clutch plate 134a made of iron and two outer clutch plates 134b made of iron.

  Furthermore, in this embodiment, the magnetic path L2 that circulates between the yoke 136, the rear housing 131b, the friction clutch 134, the armature 135, the friction clutch 134, the rear housing 131b, and the yoke 136 is generated by energizing the electromagnetic coil of the electromagnet 133. It is formed.

  As shown in FIGS. 10 and 11, a substantially mesh-like groove M is formed on the sliding surface S2 of the outer clutch plate 134b on the inner clutch plate 134a side by pressing. The groove portion M is configured to receive excess lubricating oil interposed between the clutch plates 134a and 134b. The sliding surface S1 of the inner clutch plate 134a is formed with a surface roughness (Rz) of about 13.5 μm, and the sliding surface S2 of the outer clutch plate 134b is formed with a surface roughness (Rz) of about 3.3 μm. Has been. In the present specification, “Rz” means ten-point average roughness.

  As shown in FIG. 11, the diamond-like carbon thin film D is formed on the sliding surface S2 having the groove M by a known method such as a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or an ion deposition method. Is given. Also in this embodiment, the thickness of the diamond-like carbon thin film D is 3 μm. Even if the diamond-like carbon thin film D is applied to the sliding surface S2, the surface roughness (Rz) of the diamond-like carbon thin film D is about 3.3 μm.

Next, a characteristic operation of the driving force transmission device 111 will be described.
The conventional drive transmission device shown in the following description refers to the drive force transmission device 111 in which the sliding surface S2 of the clutch plate 134b is not subjected to the diamond-like carbon thin film D but is subjected to nitriding instead. It shall be equivalent. In addition, in the friction clutch of the conventional driving force transmission device, the surface roughness (Rz) of the sliding surface of the inner clutch plate is about 7.8 μm, and the surface roughness (Rz) of the outer clutch plate is about 3.8 μm. To do.

  Hereinafter, in the friction clutch of the conventional driving force transmission device, the outer clutch plate may be referred to as “conventional outer plate” and the inner clutch plate may be referred to as “conventional inner plate”.

For comparison, it is assumed that the torque transmission capability of the conventional driving force transmission device is the same as that of the driving force transmission device 111 of the present embodiment.
FIG. 12 shows the relationship between the number of endurance cycles and “μ100 / μ50” in the driving force transmission device 111 and the conventional driving force transmission device. In FIG. 12, the vertical axis represents “μ100 / μ50” and the horizontal axis represents “endurance cycle number”.

Note that “μ100 / μ50” shown in this figure is a value obtained by dividing the friction coefficient μ at 100 min−1 by the friction coefficient μ at 50 min−1.
This can be expressed as an expression:
μ100 / μ50 = (friction coefficient μ at 100 min−1) / (friction coefficient μ at 50 min−1)
It becomes.

  If the value of “μ100 / μ50” is 1 or more, the μ-v gradient has a positive speed dependency. It is known that the judder prevention property is excellent when the μ-v gradient has a positive speed dependency.

  For example, judder means the following. The drive force transmission device 111 is mounted by the self-excited vibration of the drive system caused by the sliding surface portion between the inner clutch plate 134a and the outer clutch plate 134b or the stick / slip of the inner clutch plate 132a and the outer clutch plate 132b. A phenomenon that extends to the entire vehicle.

Next, the μ-v characteristic (μ-v gradient) will be described.
In order to suppress stick-slip on the sliding surface, it is effective that the dependence of the friction coefficient μ on the speed v (μ-v characteristic) has a positive gradient (dμ / dv ≧ 0).

  The friction generated on the sliding surface is the sum of fluid friction (shear resistance of the oil film) and boundary friction (inter-solid friction between the sliding surfaces). Their size per unit area is related to fluid friction << boundary friction. As v increases, the formation of an oil film is qualitatively promoted, the fluid friction component increases, and the boundary friction component decreases. Here, if the contact surface roughness is large, solid contact is maintained at the convex portion of the roughness even if v increases, and the decrease of the boundary friction component is suppressed (at the same time, the increase of the fluid friction component is suppressed). Acts in the direction of the positive gradient of the μ-v characteristic.

  That is, stick slip occurs due to a decrease in the surface roughness of the clutch plates 132a, 132b, 134a, 134b. Another cause of the occurrence of stick-slip is deterioration of lubricating oil due to wear powder of the clutch plates 132a, 132b, 134a, 134b.

The “number of endurance cycles” shown in this figure is one in which the value of the “number of endurance cycles” is 1 for one friction engagement in both clutch plates 134a and 134b.
Therefore, in FIG. 12, in the conventional driving force transmission device, when the value of the “endurance cycle number” is a1, the value of “μ100 / μ50” becomes 1 or less, and judder occurs.

The cause of this judder is wear on the sliding surfaces of both clutch plates of the friction clutch. Therefore, at this time, the lifetime of the conventional driving force transmission device is reached.
On the other hand, in the driving force transmission device 111, when the value of “the number of endurance cycles” is a2, the value of “μ100 / μ50” becomes 1 or less and judder occurs. At this time, the life of the driving force transmission device 111 is reached.

  As can be seen from the description of FIG. 12 described above, the outer clutch plate 134b to which the diamond-like carbon thin film D is applied has a judder resistance improvement of three times or more as compared with the conventional driving force transmission device. That is, the wear resistance of the sliding surface S2 is higher than that of the conventional outer plate. In addition, the sliding surface S1 of the inner clutch plate 134a that is in sliding contact with the diamond-like carbon thin film D is less worn than the conventional inner plate. That is, the sliding surface S2 to which the diamond-like carbon thin film D is applied plays a role of a solid lubricant that suppresses wear of the mating sliding surface S1.

  Therefore, according to the driving force transmission device 111 of the present embodiment, the life of the clutch plates 134a and 134b can be remarkably improved, and the life of the entire driving force transmission device 111 can be remarkably improved. Further, the same effects as the effects (7) and (8) of the first embodiment can be obtained, and the following effects can be obtained.

  (1) In the present embodiment, the diamond-like carbon thin film D is applied to the sliding surface S2 of the clutch plate 134b. The sliding surface S1 of the clutch plate 134a was subjected to a known nitriding treatment or a known quenching and tempering treatment. The clutch plates 134a and 134b are configured to be frictionally engaged in the lubricating oil. By the way, when a friction clutch in which nitriding treatment or quenching and tempering treatment is applied to the sliding surfaces of both clutch plates shown in the prior art is frictionally engaged in lubricating oil, both clutch plates are severely worn. However, the friction clutch 134 of the present embodiment is less likely to be worn because the diamond-like carbon thin film D is applied to the sliding surface S2 of the outer clutch plate 134b.

  Moreover, since the diamond-like carbon thin film D is a kind of carbon film, it also serves as a solid lubricant. Therefore, when the diamond-like carbon thin film D is applied to the sliding surface S2, the sliding surface S1 of the inner clutch plate 134a that is in sliding contact with the sliding surface S2 is not easily worn. Therefore, by applying the diamond-like carbon thin film D to the sliding surface S2, both the clutch plates 134a and 134b can be improved in durability. In addition, the durability of the friction clutch 134 itself is improved.

  (2) In the present embodiment, the substantially mesh-shaped groove M is provided on the sliding surface S2 of the clutch plate 134b. Accordingly, the contact area between the inner clutch plate 34a and the outer clutch plate 34b can be set to an arbitrary area. Further, by receiving excess lubricating oil interposed between the clutch plates 134a and 134b in the groove portion M of the sliding surface S2, the formation of an oil film is prevented, and the sliding characteristics of the clutch plates 134a and 134b are improved (the drag torque). Reduction, durability improvement).

(3) In the present embodiment, the diamond-like carbon thin film D is applied to the clutch plate 134b. Then, the friction clutch 134 having the clutch plate 134 b is employed in the driving force transmission device 111. Therefore, the driving force transmission device 111 with high durability of the friction clutch 134 can be obtained.
(Other embodiments)
The embodiment described above may be embodied by changing to the following other embodiments.

  In the first embodiment, the amount of the lubricating oil filled in the storage chamber K1 of the driving force transmission device 11 is set to about 80% by volume with respect to the storage chamber K1, but the lubrication of both the clutch plates 32a and 32b is performed. Any suitable amount may be filled.

  In the first and second embodiments, the diamond-like carbon thin film D is applied to the outer clutch plates 34b and 134b constituting the pilot clutch mechanisms 30d and 130d. Not only this but the clutch plate which gave the diamond-like carbon thin film D may be employ | adopted for any clutch mechanisms, such as a clutch mechanism for automatic transmissions.

In the second embodiment, the substantially mesh-like groove M is formed on the sliding surface S2 of the clutch plate 134b, but may be omitted.
-In the said 1st Embodiment, although the groove part was not provided in sliding surface S2 of the outer clutch plate 34b, you may provide the groove part similar to the groove part M of 2nd Embodiment.

In the first and second embodiments, the groove portions 40 are provided in the inner clutch plates 34a and 134a, but may be omitted.
-In the said 1st Embodiment, the outer clutch plate 34b which gave the diamond-like carbon thin film D to the friction clutch 34 was employ | adopted. Not limited to this, the diamond-like carbon thin film D may be applied to at least one of the clutch plates 32a and 32b of the main clutch mechanism 30c. Such a change may be embodied by the driving force transmission device 111 of the second embodiment.

  In the first and second embodiments, the diamond-like carbon thin film D is applied to the sliding surface S2 of the outer clutch plates 34b and 134b. Not only this but the diamond-like carbon thin film D may be given also to sliding surface S1 of inner clutch plates 34a and 134a.

  In the first and second embodiments, the diamond-like carbon thin film D is applied to the sliding surface S2 of the outer clutch plates 34b and 134b, and the known nitriding treatment is applied to the sliding surface S1 of the inner clutch plates 34a and 134a. The quenching and tempering treatment was performed. Not limited to this, the sliding surface S2 of the outer clutch plates 34b and 134b is subjected to a known nitriding treatment or a known quenching and tempering treatment, and the diamond-like carbon thin film D is applied to the sliding surfaces S1 of the inner clutch plates 34a and 134a. May be applied. In this case, the inner clutch plates 34a and 134a correspond to “one clutch plate”, and the outer clutch plates 34b and 134b correspond to “the other clutch plate”.

  In the first and second embodiments, a known nitriding process or a known quenching and tempering process is performed on the sliding surfaces S1 of the inner clutch plates 34a and 134a. Good.

Next, technical ideas that can be grasped from the above embodiment and other embodiments will be described below together with their effects.
(A) The electromagnetic drive means includes an armature and an electromagnet, and the armature, the cam mechanism, and a seal member constitute a seal mechanism, and the storage chambers are sealed with each other by the seal mechanism. Features.

In this case, the lubricating oil in the space filled with the lubricating oil can be prevented from leaking into the space not filled with the lubricating oil by the armature, the cam mechanism, and the seal member.
(B) The clutch plate is made of iron and has a diamond-like carbon thin film on the sliding surface.

  (C) The friction clutch is provided with a plurality of iron clutch plates that are frictionally engaged with each other, and the one clutch plate that is frictionally engaged with each other is constituted by a clutch plate having a sliding surface provided with a diamond-like carbon thin film. And

(D) The sliding surface of the other clutch plate of the friction clutch is subjected to nitriding treatment or quenching and tempering treatment.
(E) The sliding surface of the other clutch plate is provided with a plurality of grooves provided along the circumferential direction.

(F) The sliding surface of the one clutch plate is provided with a substantially mesh-shaped groove.
(G) The driving force transmission device is provided between both the inner and outer rotating members positioned so as to be relatively rotatable with each other, and is provided with a clutch portion in each of a plurality of sealed storage chambers. A driving force transmission device capable of transmitting torque between members, wherein at least one of the storage chambers is an unfilled space for lubricating oil, and the other storage chamber is a filled space for lubricating oil, and the unfilled space The clutch portion is constituted by the friction clutch, and an electromagnetic driving means for connecting and disconnecting the friction clutch is provided, and the friction clutch performs dry friction engagement when the driving means is operated.

  (H) The clutch portion located in the filling space is a main clutch that is located between the inner and outer rotating members and transmits torque between the inner and outer rotating members by friction engagement, and the friction clutch and the electromagnetic type The driving means constitutes a pilot clutch mechanism, and includes a cam mechanism that frictionally engages the main clutch by transmitting the friction engagement force of the pilot clutch mechanism to the main clutch.

  (I) The driving force transmission device is provided between the inner and outer rotating members positioned so as to be rotatable relative to each other, and a plurality of clutch portions are provided in a storage chamber filled with lubricating oil. A driving force transmission device capable of transmitting torque between both rotating members, wherein at least one clutch portion in the storage chamber is configured by the friction clutch.

  (Nu) An electromagnetic driving means for connecting / disconnecting the friction clutch is provided, and a clutch portion other than the friction clutch is provided in the storage chamber to transmit torque between the inner and outer rotating members by friction engagement. A clutch mechanism is constituted by the friction clutch and the electromagnetic drive means, and a cam mechanism that frictionally engages the main clutch by transmitting the friction engagement force of the pilot clutch mechanism to the main clutch. It is characterized by that.

The fragmentary sectional view of the driving force transmission device in a 1st embodiment. Explanatory drawing of the four-wheel drive vehicle carrying the driving force transmission apparatus in 1st Embodiment. Explanatory drawing which shows the cross section of both clutch plates 34a and 34b in 1st Embodiment. The front view which shows the inner clutch plate 34a in 1st Embodiment. The elements on larger scale of the driving force transmission apparatus in FIG. The characteristic view which showed the relationship between the rotation speed of the inner shaft in a conventional driving force transmission device, and drag torque. The characteristic view which showed the drag torque in the conventional driving force transmission device and the driving force transmission device 11. Schematic explanatory drawing which shows the apparatus for shape | molding a diamond-like carbon thin film in the outer clutch plate 34b. The fragmentary sectional view of the driving force transmission device in a 2nd embodiment. The front view of the outer clutch plate 134b in 2nd Embodiment. Explanatory drawing which shows the cross section of both clutch plates 134a and 134b in 2nd Embodiment. The characteristic view which showed the relationship between "the number of endurance cycles" and "μ100 / μ50".

Explanation of symbols

11, 111 ... Driving force transmission device,
30a, 130a ... outer case as an outer rotating member,
30b, 130b ... Inner shaft as inner rotating member,
30c, 130c ... main clutch mechanism as a clutch part and a main clutch,
30d, 130d ... pilot clutch mechanism, 30e, 130e ... cam mechanism,
34, 134 ... friction clutch as a clutch part,
34a, 134a ... inner clutch plate as the other clutch plate, 34b, 134b ... outer clutch plate as one clutch plate, 40 ... groove portions as "a plurality of groove portions provided along the circumferential direction",
D ... Diamond-like carbon thin film, K1, K2 ... Storage room,
M: groove part as “substantially mesh-like groove part”, S1, S2: sliding surface

Claims (6)

A driving force transmission device that is disposed between rotating members positioned so as to be rotatable relative to each other and frictionally engages to transmit driving force between these rotating members,
A driving force transmission device, characterized in that a diamond-like carbon thin film having an amorphous structure is applied to one of sliding surfaces that are frictionally engaged. The driving force transmission device according to claim 1, wherein lubricating oil is interposed between the sliding surfaces, and wet friction engagement is performed. The driving force transmission device according to claim 1 or 2, wherein the other sliding surface is subjected to nitriding treatment or quenching and tempering treatment. The driving force transmission device according to any one of claims 1 to 3, wherein a plurality of minute width grooves provided along the circumferential direction are formed on the other of the sliding surfaces. 5. The driving force transmission device according to claim 2, wherein a substantially mesh-shaped groove is formed on the one sliding surface. 6. The driving force transmission device according to any one of claims 1 to 5, wherein the driving force transmission device transmits a driving force of a vehicle.

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