JPH0419425A - Wet clutch - Google Patents

Abstract

PURPOSE:To reduce drag torque by forming a passage, which is for supplying air to contact surfaces of both plates, in at least one of the drive plate or the driven plate. CONSTITUTION:In the case of a large rotational speed of a drive plate 12, centrifugal force, acting on lubricating oil 24, is also increased, so that the lubricating oil exceeds a supply amount by increasing a flow speed of the lubricating oil 24. Under this condition, air is started to infiltrate between both plates 12, 14 from a side of the stationary plate 14 by generating a negative speed and exfoliation of the lubricating oil 24 in a side of the driven plate 14, and air and the lubricating oil 26 are violently mixed and discharged in the peripheral direction by a flow in the vicinity of the rotating plate 12. In this way, drag torque is reduced by decreasing a drag of the lubricating oil 24. Here, an inflow of air is easily generated along a groove 22 between the plates 12, 14 by forming the groove in the plate 14, and the air is mixed in the lubricating oil 24 from a region of small relative rotation between both the plates.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a wet clutch.

Conventional technology In general, a clutch is used to cut off and continue power.
There are two main types of clutches: dry type, which uses friction plates in a dry state, and wet type, which uses lubricating oil to the friction plates. For example, the latter wet type clutch has multiple plates and is used automatically. It is used as a plurality of friction elements built into a transmission (see 1937 edition of Nl5SAN Full Range Electronically Controlled Automatic Transmission Maintenance Manual Model RE4ROIA).

By the way, in such a wet type multi-disc clutch, a plurality of drive plates and a plurality of driven plates are arranged alternately and overlapped with each other, and when these drive plates and driven plates are brought into pressure contact, they are in a fastened state and power is generated. Transmission is possible, and on the other hand, when the pressure contact is released, it becomes a released state and power transmission is cut off.

Problems to be Solved by the Invention However, in such conventional wet clutches, in order to perform quick engagement, the distance between the drive plate and the driven plate is made small.

For this reason, even when the clutch is in the released state, lubricating oil is maintained between both plates, and due to the viscosity of the lubricating oil, trough torque is generated when the drive plate and driven plate are rotated relative to each other. .

Therefore, the trough torque causes a power loss, resulting in deterioration of fuel efficiency.

In particular, at low temperatures, the viscosity of the lubricating oil increases, so the above-mentioned trough torque increases compared to at high temperatures, and in automatic transmissions that use wet clutches, power is transmitted even in the N range (neutral). There were some issues.

SUMMARY OF THE INVENTION In view of these conventional problems, it is an object of the present invention to provide a wet clutch that can increase separation of lubricating oil between a drive plate and a driven plate, thereby reducing trough torque. .

Means for Solving the Problems In order to achieve the above objects, a first configuration of the present invention provides a wet type clutch comprising a drive plate and a driven plate which are superposed on each other, and a lubricating oil is supplied between these two plates. In this step, a passage is formed in at least one of the two drive plates or the driven plate for supplying air to a contact surface of these two plates.

(f2) In order to achieve such an object, a second configuration of the present invention is a wet type clutch that includes a drive plate and a driven plate that are superposed on each other, and in which lubricating oil is supplied between these two plates. A spiral groove is formed in at least one of the plate or the driven plate for forcibly discharging lubricating oil interposed between the two plates.

Furthermore, a third configuration of the present invention is a wet clutch that includes a drive plate 1 and a driven plate that are superposed on each other, and in which lubricating oil is supplied between these two plates.
The gap between the drive plate and the driven plate 1 is made larger at the outer periphery than at the center.

Operation With the above-described structure, the wet type clutch of the first structure of the present invention is such that when the clutch is in a released state, that is, a disengaged state, the drive plate and the driven plate are rotated relative to each other, so that the wet clutch is interposed between these two plates. The lubricating oil tends to flow toward the outer circumference due to centrifugal force.

When the rotation speed of the plate reaches a predetermined rotation speed, the amount of lubricating oil discharged between the two plates exceeds the supply amount, so air flows between the two plates through the passage, and the air mixes with the lubricating oil. to promote the removal of lubricating oil.

Because of the second reason, the trough torque generated between the drive plate and the driven plate is reduced, but the formation of the passage allows air to flow in from the low rotation range easily, which significantly reduces the trough torque. I can do it.

Furthermore, the wet clutch shown in the second configuration of the present invention is)
By forming a spiral groove on the contact surface of at least one of the live plate or the driven plate, the spiral groove acts as a centrifugal pump to pump both plates Ii-+'i :)''
) Actively drain the lubricating oil, tJ, both plays 1.
Second, it is possible to reduce the trough torque.

Historically, in the wet clutch shown in the third configuration of the present invention, the gap between the drive plate and the driven plate was formed to be larger at the outer periphery than at the center, so that the lubricating oil passage formed by both plates could be drained. Since the opening is widened and air is drawn in at the discharge opening and can be promoted to flow between the two plates, the drag and torque can be significantly reduced.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIGS. 1 and 2 show a first embodiment of the present invention, and take as an example the case where the present invention is applied to a wet multi-disc clutch 10 (low and reverse brake) used in an automatic transmission. explain.

The types of friction elements to be incorporated into automatic transmissions are disclosed in, for example, Japanese Patent Application Laid-Open No. 62-62047.

In FIG. 1, 12 is a drive plate, and 14 is a driven plate, and these drive plates 12 and driven plates 14 are alternately arranged in multiple stages and overlapped with each other.

The drive plate 12 is engaged with the spline 16a of the clutch hub 16 via a plurality of radial protrusions 12λ formed on the inner circumference, and the driven plate 14
is engaged with a spline 18a of the case I8 via a plurality of radial projections 14a formed on the outer periphery.

Therefore, when the drive plate 12 and the driven plate 14 are pressed together, that is, when the clutch 10 is engaged and f2, the rotation of the clutch hub 16 is prevented by the stationary case 18, and the clutch IO is Functions as a brake.

Frictional materials 20 are fixed to both sides of the drive plate I2, and when fastened, the frictional materials 20 are attached to the driven plate 14.
By making contact with the material, the frictional force can be increased and a reliable connection can be achieved.

In this embodiment, the drive plate 12 and the driven plate 14 have a smaller absolute value of rotation speed, that is, on both sides of the driven plate 14 engaged with the case 18, as shown in FIG. In this way, radial grooves 22 are formed as air passages.

The groove 22 is formed so that the inner circumference and outer circumference of the driven plate 14 communicate with each other.

Note that a spline 16a of the clutch hub 16 is provided between the drive plate 12 and the driven plate 14.
Lubricating oil is supplied from the inner circumferential direction to the outer circumferential direction of both plates 1214 through the gap.

With the above configuration, the wet multi-disc clutch IO of this embodiment is
When the drive plate 12 and the driven plate 14 are separated and in the released state, the lubricating oil 24 is interposed approximately evenly between the two plates 124, as shown in FIG. As the plate 12 is rotated, centrifugal force acts on the lubricating oil 24, increasing the movement speed in the outer circumferential direction.

and the relative rotation between both plates 12.14, i.e.
When the rotational speed of the drive plate 12 is low, the lubricating oil 24 flows between both brakes 12 and 14 while maintaining a laminar flow state, and the flow velocity distribution at this time is as shown in FIG. 4(a). It is fast in the center of plate I214 and slow at both ends.

Next, FIG. 3(a) shows a case where the rotational speed of the drive plate 12 is high. In this case, the centrifugal force acting on the lubricating oil 24 also increases, so the flow rate of the lubricating oil 24 is increased and the supply amount is increased. exceed.

In this state, as shown in the flow velocity distribution in FIG. 4(b), a negative velocity (reverse flow in the opposite direction to the centrifugal force) is generated on the driven plate 14 side, and as a result, a negative velocity is generated on the driven plate 14 side. When the lubricating oil 24 peels off, the lubricating oil 24 is stopped and the
From this driven plate 14 side, both plates 12.14
Air begins to enter the gate and the drive plate 12 rotates.
Due to the nearby flow, the air and lubricating oil 24 fit together violently, and in this state they are discharged toward the outer circumference.

Therefore, when the relative rotation between the drive plate 12 and the driven plate 14 is large like this, the lubricating oil 24
The separation of the lubricating oil 24 reduces the drag of the lubricating oil 24 and reduces the drag torque.

In the figure, the flow of air is shown by broken line arrows, and the flow of lubricating oil 24 is shown by solid line arrows.

By the way, in this embodiment, as shown in FIG. 5, since the groove 22 is formed in the driven plate 14, the groove 2
Air passes through the drive plate 12. Air easily flows between the driven plates 14, and mixing of air and lubricating oil 24 occurs from a region where the relative rotation between the drive plate 12 and the driven plate 14 is small.

Figure 6 shows the drive plate 12 and driven plate I4.
The solid line in the figure shows the drag torque characteristic A when the conventional passage is not formed, and the broken line shows the drag torque characteristic A when the groove 22 of this embodiment is not formed.
is formed and shows the drag torque characteristic B in this case.

As is clear from this characteristic diagram, in the case of this embodiment, the relative rotational speed when air is mixed into the lubricating oil 24 is low, so it is understood that the drag torque is significantly reduced compared to the conventional one. Ru.

FIG. 7 shows a second embodiment of the present invention, which differs from the first embodiment in that a groove 22A is provided at the radial protrusion 14a of the driven plate 14.

This is because lubricating oil tends to accumulate in the gap α (see Fig. 7a) between the protrusion of the spline portion 18a of the case 18 and the outer periphery of the driven plate 14, whereas the spline? AI 8
This is because lubricating oil does not accumulate between the concave portion a and the outer periphery of the radial protrusion 14a, making it suitable for introducing air.

8 and 9 show a third embodiment of the present invention, and FIG.
．． The same components as in the second embodiment are given the same reference numerals, and redundant explanations will be omitted.

That is, in this embodiment, in place of the groove 22 of the first embodiment, a through hole 30 is formed that penetrates the driven plate 14 in the radial direction, and the drive plate 12 is connected to the through hole 30. A communication hole 32 is formed in the contact surface with the friction material 20, and these through holes 30 and the communication hole 32
An air passage 34 is formed by this.

Therefore, in this embodiment as well, as in the first embodiment, the drive plate 1 is
Air can be actively supplied to the lubricating oil 24 layer between the lubricating oil 2 and the driven plate 14, and a significant reduction in trag torque can be achieved.

By the way, in this third embodiment, driven play)
Since only the communicating holes 32 are formed on the contact surfaces of the 14 friction materials 20, the radial grooves 22.
22A, the wear of the friction material 20 can be significantly reduced.

Additionally, in this embodiment, by forming a circumferential annular groove in the portion of the friction material 20 facing the communication hole 32, the wear resistance of the friction material 20 is further improved. That will happen.

Even in this third embodiment, if the opening of the through hole 30 on the outer periphery of the driven plate is provided corresponding to the position of the radial protrusion 14a of the driven plate 14 as in the second embodiment,
more effective.

In addition, in the first to third embodiments described above, the air passage is formed on the driven plate 14 side, but by forming the air passage on the side where the absolute value of the rotational speed is small in this way, the air It is preferable that an air passage be formed in the driven plate 14 because the inflow effect of the air can be further increased.

FIG. 10 shows a fourth embodiment of the present invention, and the same components as those of the above embodiments are given the same reference numerals and redundant explanations will be omitted.

That is, instead of the grooves 22.22A in the 1.2 embodiment being formed linearly in the radial direction of the driven plate 14, in the fourth embodiment, a plurality of grooves are formed in the friction material 20 of the drive plate 1-12. The spiral groove 4o is formed as a passage.

The spiral TR40 is known to have an Archimedean spiral shape or a logarithmic spiral shape, and the inner radius of the friction material 20 in which the spiral groove 40 is formed is r. , outside +′ = diameter rl,
If the arbitrary radius of the spiral is r, and the angle from the predetermined position of the part corresponding to the radius r is θ, then Archimedes' spiral is expressed as r-rQ-aθ...■, Logarithmic spiral It is expressed in the form (r ro)2=aθ...■.

Therefore, in this embodiment, the spiral groove 40 is formed in the friction material 20 of the drive plate 12, so that when the drive plate 12 is rotated, the gap between the drive plate 12 and the driven plate 14 is reduced by a kind of centrifugal pump. The amount of lubricating oil flowing out along the spiral groove 40 increases significantly.

As a result, the amount of lubricating oil between the plates 12 and 14 is discharged from the gap, which is significantly greater than the amount supplied, and the amount of air that enters between the plates 12 and 14 increases accordingly, causing the lubricating oil to separate. The reduction in trough torque is further promoted, and a significant reduction in trough torque can be achieved.

The spiral groove 40 preferably has a logarithmic spiral shape in terms of discharge capacity when the ratio λ=ro/r of the inner radius rO and the outer radius r1 of the friction material 20 is 075 or less; In this case, an Archimedean spiral is preferred.

Moreover, the same function can be obtained even if the spiral groove 40 is formed not on the drive plate 12 side but on the driven plate 14 side.

FIG. 11 shows a fifth embodiment of the present invention. In this embodiment, a chamfered portion 2
By providing a chamfered portion +4b on the outer periphery of the driven plate 14 as well as providing a chamfered portion +4b, the gap C between the drive plate 12 and the driven plate I4 is set so that the inner diameter of the friction material 20 of the drive plate 12 is r. , when the outer diameter is rl, the central part, that is, [(r o'-, r 1) /
2] The gap C2 at the outer peripheral portion is made larger than the gap C1 at the portion (see Fig. 12).

Therefore, the drive plate 12 and the driven plate 14
The lubricating oil flow path is formed in the gap between the discharge side (outer circumferential side)
As the aperture becomes wider, the backflow phenomenon described in the first embodiment is more likely to occur, and compared to the conventional structure where the entire gap is formed as a uniform gap, as shown in FIG. The amount of air entering between plates 12 and 14 increases,
Trough torque is reduced.

FIG. 14 shows a sixth embodiment of the present invention, in which the fifth embodiment is the drive plate 12. Driven plate 14
While a chamfered portion is provided on the outer periphery, the thickness of the friction material 20 is determined so that the thickness of the inner and outer peripheries of the drive plate I2, b', satisfies b>b'. The plate thickness of I4 is also that the outer circumference a' is a> compared to the inner circumference a.
&′.

Therefore, as in the fifth embodiment, the gap between the drive plate and the driven plate is larger at the outer periphery than at the center, so the amount of air that enters between the two plates at low rotation speeds is increased compared to the conventional case. and the trough torque is reduced.

As described in the detailed description of the invention, in the wet clutch according to claim 1 of the present invention, an air passage is formed in at least one of the drive plate or the driven plate for supplying air to the contact surface of these two plates. Therefore, air can easily flow in through the air passage, and the trough torque generated between the drive plate and the driven plate can be significantly reduced.

In addition, in the wet clutch according to claim 2 of the present invention, a spiral groove is formed on the contact surface of at least one of the drive plate or the driven plate, so that the spiral groove acts as a centrifugal pump to cause both plates to By actively discharging the lubricating oil between the two plates, it is possible to promote the inflow of air between the two plates, thereby significantly reducing the drag torque.

Furthermore, in the wet clutch according to claim 3 of the present invention, the gap between the drive plate and the driven plate is formed to be larger at the outer periphery than at the center. In addition to being able to easily allow air to flow in through the drive plate, the trough torque generated between the drive plate and the driven plate can be significantly reduced, which provides various excellent effects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a first embodiment of the present invention, FIG. 2 is a front view of a driven plate used in the first embodiment of the present invention, and FIGS. 3(a) and (b) are drive plates. Explanatory diagrams showing the flow state of lubricating oil between the plate and the drive plate, Figures 4(a) and (b) are the same as Figures 3(a) and (b).
), FIG. 5 is an explanatory diagram showing the flow state of lubricating oil in the first embodiment of the present invention, and FIG.
The figure is a drag torque characteristic diagram comparing the present invention and the conventional one, Figure 7 is a sectional view of the main part showing the uninvented second embodiment, and Figure 7a is an enlarged view of the ■ part in Figure 7. , FIG. 8 is a cross-sectional view of a main part showing a third embodiment of the present invention, FIG. 9 is a front view of a driven plate used in the third embodiment, and FIG. 1O is used in a fourth embodiment of the present invention. Front view of drive plate,
FIG. 11 is a cross-sectional view of essential parts showing the uninvented fifth embodiment;
Fig. 2 is a graph showing the relationship between the distance between the drive plate and the driven plate and the clutch radius in the fifth embodiment, Fig. 13 is an explanatory diagram showing the flow state of lubricating oil in the fifth embodiment, and Fig. 14 FIG. 7 is a sectional view of a main part showing a sixth embodiment of the present invention. IO...Wet type multi-plate clutch (wet type clutch), 12.
...Drive plate, 14...Driven plate,
20...Friction material, 22.22A...Groove (air passage)
, 24... Lubricating oil, 34... Air passage, 40...
Spiral groove, C... gap. Figure ■ Figure (a) Figure (G) Figure (b) Figure (b) Figure Shomura rotation construction Figure 1 Figure 12 Figure 13

Claims (3)

[Claims] (1) In a wet clutch that includes a drive plate and a driven plate that overlap each other, and in which lubricating oil is supplied between these two plates, at least one of the drive plate or the driven plate has a contact surface between the two plates. A wet clutch characterized by forming an air passage for supplying air. (2) In a wet clutch that includes a drive plate and a driven plate that overlap each other, and in which lubricating oil is supplied between these two plates, a contact surface of at least one of the drive plate or the driven plate is provided with a A wet clutch characterized by forming a spiral groove for forcibly discharging lubricating oil interposed in the clutch. (3) In a wet clutch that includes a drive plate and a driven plate that overlap each other, and in which lubricating oil is supplied between these plates, the gap between the drive plate and the driven plate is
A wet clutch characterized by the outer circumference being larger than the center.