KR20180007238A - Friction pad for wet clutch system and wet multi plate clutch having this - Google Patents

Abstract

The present invention relates to a friction pad for a wet clutch (130) and a wet multi-plate clutch having the same. According to the present invention, the friction pad for the wet clutch comprises: a ring-shaped core plate (131); and a plurality of friction segments (135) placed on the core plate (131) at regular intervals. On an external surface of the core plate (131) and the friction segments (135) facing a separate plate (120) formed a pad groove (137) to connect the inner circumferential surface and an outer circumferential surface of the core plate (131). On the pad groove (137) formed is a diffusion unit (137c) which expands in a rotational direction of the core plate (131). The pad groove (137) is asymmetrical. The present invention is able to discharge transmission oil more rapidly and actively through the shape of the pad groove (137), thereby greatly reducing drag torque and the resulting power loss of a clutch apparatus.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a friction pad for a wet clutch and a wet multi-

The present invention relates to a friction pad for a wet clutch, and more particularly, to a friction pad for a wet clutch having a groove shape for use in a dual clutch transmission of an automobile and for reducing a drag torque and a wet type multiplate clutch having the friction pad.

In the field of transmission, the dual clutch transmission (hereinafter referred to as 'DCT'), which is combined with the advantages of a manual transmission having excellent fuel economy and sporty driving performance, an advantage of an automatic transmission having a driving convenience and a smooth shifting performance Research is actively being carried out.

The basic structure of the DCT is divided into two clutches and a synchronizer, which is a gear engagement structure. One clutch is connected to the engine and the other clutch is disengaged, and the synchronizer is tightened. Then, the two clutches are released and connected to perform shifting to the next speed change gear. This shift process minimizes the power cut-off interval and improves the acceleration performance. At the same time, it automates the operation of the clutch and the synchronizer with the actuator to enhance the driver's convenience.

Such a dual clutch device can be classified into a dry clutch whose surface of the clutch plate is operated by dry friction and a wet clutch which transmits power by engaging the clutch plate in the transmission fluid.

Among them, the ability of the wet clutch is greatly influenced by the drag torque. The drag torque occurs in the ready to fasten state, more specifically, due to the flow shear resistance of the transmission fluid present in the contact surface clearance between the separate plate and the friction pad. This drag torque not only reduces the efficiency of the system due to power loss, but also affects the shift timing. Therefore, the design for reducing drag torque is an important factor that enables efficient use and distribution of engine power and improves fuel economy.

Korean Patent Publication No. 10-2016-0064090

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the drag torque by discharging the transmission fluid present between the separate plate and the contact pad more quickly.

According to an aspect of the present invention for achieving the above-mentioned object, the present invention provides a core plate comprising an annular core plate and a plurality of friction segments provided at regular intervals on the core plate, The outer surface of the plate and the frictional segment is formed by recessing a pad groove connecting the inner circumferential surface and the outer circumferential surface of the core plate, and the pad groove is formed with a diffusion portion extending in the rotational direction of the core plate.

The core plate having an inlet portion extending from the inner circumferential surface of the core plate, an outlet portion connected to the inlet portion and enlarged toward the outer circumferential surface of the core plate, and an outlet portion connected to the outlet portion, And a diffusion portion for widening the width of the outlet portion.

The diffuser extends linearly from the inlet, and the angle between the inlet and the diffuser is between 140 ° and 145 °.

The diffusing portion extends in a curved shape from the inlet portion, and an angle between imaginary extension lines connecting the inlet portion and the diffusing portion is 135 to 140 degrees.

The pad groove is recessed through the friction segment to the outer surface of the core plate.

According to another aspect of the present invention, there is provided a clutch hub comprising: a clutch housing; a piston mounted within the clutch housing and receiving a pressure of the transmission oil; a clutch hub disposed in the clutch housing and mounted on an output shaft; And a clutch plate having a plurality of separate plates to which pressure is applied from the piston, and friction pads alternately arranged with the separate plates, wherein an outer surface of the friction pad is provided with a pad groove And the pad groove is formed with a diffusion part extending in the rotational direction of the friction pad, so that the pad groove is asymmetric.

Wherein the pad groove comprises an inlet portion extending from the inner circumferential surface of the friction pad, an outlet portion connected to the inlet portion and enlarged toward the outer circumferential surface of the friction pad, And a diffusion portion for widening the width of the outlet portion. The diffusion portion extends linearly from the inlet portion, or the diffusion portion extends from the inlet portion in a curved shape.

The friction pad for a wet clutch according to the present invention as described above and the wet type multi-plate clutch having the friction pad have the following effects.

In the present invention, the pad groove formed on the friction pad is an asymmetric shape expanded along the rotational direction of the friction pad. Since the transmission oil can be discharged more quickly and smoothly through the pad groove shape, the drag torque of the clutch device and thus the power loss are greatly reduced, and as a result, the efficiency of the system is improved.

In the present invention, the fuel consumption can be improved by reducing the drag torque, and the time lag and the shift shock can be reduced at the time of shifting engagement by inducing quick discharge of the transmission oil present in the clutch contact gap, Improvement is achieved.

In addition, since the transmission oil is rapidly discharged, the frictional heat acting on the clutch plate can be quickly discharged, thereby improving the cooling efficiency.

Particularly, it is possible to bring about the above-mentioned effects only by changing the shape of the pad groove, so that it is not necessary to redesign the clutch device as a whole, and it can be applied to the conventional clutch device as it is, .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing the construction of a wet-type multi-plate clutch to which an embodiment of a friction pad for a wet clutch according to the present invention is applied.
Fig. 2 is an enlarged view of a portion A in Fig. 1; Fig.
3 is a plan view showing a partial configuration of a first embodiment of a friction pad for a wet clutch according to the present invention.
4 is a plan view showing a partial configuration of a second embodiment of a friction pad for a wet clutch according to the present invention;
5 is a sectional view taken along the line a-a 'of FIG. 3;
6 (a) and 6 (b) are conceptual diagrams showing the pad groove shapes in the first and second embodiments shown in Figs. 3 and 4, respectively.
7 is a conceptual diagram simulating the flow of a transmission fluid when a second embodiment of a friction pad for a wet clutch according to the present invention is applied.
8 is a graph comparing the magnitude of a drag torque generated when a friction pad for a wet clutch according to the present invention is applied, in comparison with the prior art.
9 is a graph comparing the reduction rate of the drag torque generated when a friction pad for a wet clutch according to the present invention is applied, compared with the prior art.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the understanding why the present invention is not intended to be interpreted.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

1, a wet multi-plate clutch is shown. A wet clutch according to the present invention includes a clutch housing (11), a piston (12), a clutch hub (13), and a clutch plate (100).

The piston 12 is mounted in the clutch housing 11 and is capable of performing piston motion by receiving the pressure of the transmission oil flowing into the clutch housing 11. [ The clutch hub 13 is disposed in the clutch housing 11 and mounted on the output shaft. As the clutch hub 13 is mounted on the output shaft, the rotational force transmitted to the clutch hub 13 rotates the output shaft of the transmission.

The clutch plate 100 includes a plurality of separate plates 120 connected to the clutch hub 13 to receive pressure from the piston 12 and friction pads 130 alternately arranged with the separate plates 120. [ Respectively. Here, the plurality of separate plates 120 and the friction pads 130 are fastened to each other by the pressure of the transmission oil supplied to the piston 12.

Since the separate plates 120 and the friction pads 130 are engaged with each other by the pressing force of the transmission oil supplied to the piston 12 in this way, the friction between the separate plates 120 and the friction pads 130 Is transmitted to the output shaft of the transmission via the clutch hub 13 side, whereby the vehicle is shifted and the vehicle is driven.

When the hydraulic pressure applied to the piston 12 is released, the piston 12 is returned to its original position by the restoring force of the elastic member 15 disposed between the piston 12 and the clutch hub 13, .

The clutch hub 13 includes an inner clutch hub 13 and an outer clutch hub 13. The piston 12 is mounted in the clutch housing 11 and receives pressure from the transmission oil passage. The clutch plate 100 includes a first clutch plate 110 connected to the inner clutch hub 13 and receiving pressure from the first piston 12a and a second piston 12b connected to the inner clutch hub 13, And a second clutch plate 150 connected to the outer clutch hub 13 and receiving pressure from the second piston 12b.

That is, the wet clutch of the present invention can be applied to a dual clutch transmission (DCT: Dual Clutch Transmission) having two clutch hubs 13 and two pistons 12 and clutch plates 100, respectively. The dual clutch transmission is an automatic manual transmission in which a clutch plate 100 for taking an odd gear and a clutch plate 100 for taking an even gear are mounted on a structure of a manual transmission having a high efficiency, The other side can prepare for shifting in advance, so that the power loss is small and the shift timing is quick. Here, since the operation of the dual clutch transmission is a known technique, it is omitted.

Next, the friction pad 130 constituting the clutch plate 100 will be described in detail with reference to FIG. 2 is an enlarged perspective view of part A of FIG. The friction pad 130 is formed in a ring shape, where 'pad' is an arbitrary term and can be defined in various terms such as a friction plate or a friction disk.

The friction pad 130 has an annular core plate 131 which forms a skeleton thereof. The core plate 131 is adjacent to the separate plate 120 and has a predetermined gap therebetween so that oil can pass therethrough. 1, the arrow indicates the direction in which the transmission fluid flows and is discharged.

The core plate 131 is provided with a friction segment 135. The frictional segments 135 are connected to the outer surface of the core plate 131 at regular intervals and can be seen as a portion that is substantially in contact with the separate plate 120. As shown in FIG. 3, the friction segments 135 are formed in a substantially rectangular shape, and a plurality of the friction segments 135 are disposed at regular intervals to form an oil inflow channel (not shown) between them in the form of a net or a waffle .

At this time, a pad groove 137 is formed in the friction pad 130. The pad groove 137 is formed on the outer surface of the core plate 131 and the friction segment 135 facing the separate plate 120 so that the transmission fluid can pass through the pad groove 137. The pad groove 137 is formed across the friction pad 130 in such a manner as to connect the inner circumferential surface I and the outer circumferential surface O of the friction pad 130. That is, the pad groove 137 may be formed in the radial direction of the friction pad 130.

The shape of the pad groove 137 is well shown in FIGS. 3 and 4. FIG. 3, the pad groove 137 includes an entrance portion 137a, an exit portion 137b, and a diffusion portion 137c. The inlet portion 137a extends from the inner circumferential surface I of the core plate 131 and extends with a constant width as shown in FIG. The mouth portion is formed at a predetermined distance from the inner circumferential surface I of the friction pad 130 in the direction of the outer circumferential surface (O). Of course, the inlet portion 137a need not necessarily have a constant width, and may have a somewhat wider width in the direction of the outer peripheral surface O, or may extend in a curved shape.

The outlet portion 137b of the pad groove 137 is connected to the inlet portion 137a and extends toward the outer circumferential surface O of the friction pad 130. [ The outlet portion 137b has a larger width than the inlet portion 137a. More precisely, the outlet portion 137b has a shape enlarged so as to gradually increase in width toward the outer peripheral surface O of the friction pad 130. This allows the transmission oil to be discharged more smoothly.

Meanwhile, a diffusion portion 137c is connected to the outlet portion 137b. The diffusion portion 137c is connected to the outlet portion 137b and extends along the rotation direction of the friction pad 130 to widen the width of the outlet portion 137b. That is, the diffusion portion 137c is formed only on one side (the left side in FIG. 3) of the rotational direction of the friction pad 130 from both sides of the outlet portion 137b. As a result, the pad groove 137 has an asymmetric shape .

The diffusion portion 137c smoothly and rapidly discharges the transmission oil, so that the drag torque of the clutch device and the corresponding power loss are greatly reduced in the tightening ready state. In addition, the diffusion portion 137c induces rapid release of the clutch oil in the clutch contact gap, that is, between the friction pad 130 and the separate plate 120, thereby reducing the time lag and shift shock at the time of shifting engagement So that the frictional heat acting on the clutch plate 100 can be quickly discharged.

As shown in FIG. 3, the diffusion portion 137c extends linearly from the inlet portion 137a. Preferably, the angle between the inlet portion 137a and the diffusion portion 137c is in the range of 140 ° to 145 °. This is to prevent the transmission fluid from being discharged quickly and smoothly but excessively. In this embodiment, the angle between the inlet portion 137a and the diffusion portion 137c is 142.5 degrees.

Meanwhile, as shown in the second embodiment of FIG. 4, the diffusion portion 137c may extend in a curved shape from the inlet portion 137a. The curved diffusion portion 137c is formed only on one side (the left side in FIG. 4) of the rotational direction of the friction pad 130 from both sides of the outlet portion 137b. As a result, the pad groove 137 has an asymmetric shape .

As shown in FIG. 4, the angle between imaginary extension lines connecting the inlet portion 137a and the diffusion portion 137c is 135 ° to 140 °. Similar to the embodiment of FIG. 3, this is to prevent the transmission fluid from being discharged quickly and smoothly but not excessively. In this embodiment, the angle between the inlet portion 137a and the diffusion portion 137c is 137.5 degrees .

5, the pad groove 137 extends through the friction segment 135 and reaches the outer surface of the core plate 131. As shown in FIG. Of course, the pad groove 137 may be recessed only to a depth corresponding to a part of the thickness of the friction segment 135, but in this embodiment, it is recessed to the outer surface of the core plate 131.

Hereinafter, test results of the wet type multi-plate clutch having the friction pad 130 according to the present invention will be described.

7 is a graph simulating the flow of a transmission fluid when a second embodiment of a friction pad 130 for a wet clutch according to the present invention is applied. For reference, in this test, the film thickness of the gap between the adjacent clutches is 0.3 mm and the temperature condition is 40 ° C. 7, the space between the friction pad 130 and the separate plate 120 is modeled as a three-dimensional shape. Accordingly, the shape of the pad groove 137 is shown as protruding.

The lines in FIG. 7 indicate the flow of the fluid, that is, the transmission oil. As shown in FIG. 7, the flow is more smooth at the outlet portion 137b than at the inlet portion 137a of the pad groove 137, ) Shows the most active fluid flow. Based on the results of the simulation, it can be seen that the transmission oil flow can be discharged more quickly and smoothly through the shape of the pad groove 137 of the present invention, which in turn reduces the drag torque of the clutch device and hence the power loss .

Fig. 8 shows the result of calculating the drag torque value. 8, the pad grooves 137 of the first embodiment and the second embodiment of the present invention are compared with the pad grooves 137 having a basic Y-shape, that is, left and right symmetrical shapes. As can be seen, as the clutch plate 100 is rotated at a constant speed or more, the drag torque value of the present invention is significantly reduced from the drag torque value in the case of having the basic Y-shaped pad groove 137. More precisely, the drag torque value greatly decreased in the case where the friction pad 130 according to the present invention was applied while exceeding 1000 rpm.

When the first embodiment and the second embodiment are compared with each other, although the first embodiment produces a small amount of drag torque, the difference is not large, and when the second embodiment is applied at 1500 rpm or less, the drag torque is small Respectively.

Fig. 9 shows the reduction rate of the drag torque value. As 1500 rpm was exceeded, the drag torque greatly decreased in both the first and second embodiments.

As described above, in the present invention, drag torque reduction can be obtained by inducing quick discharge of the transmission oil present in the clutch contact gap, and time lag and shift shock can be reduced at the time of shifting engagement.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. Furthermore, the terms "comprises", "comprising", or "having" described above mean that a component can be implanted unless otherwise specifically stated, But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

11: clutch housing 12: piston
13: clutch hub 15: elastic member
100: clutch plate 120: separate plate
130: Friction pad 131: Core plate
135: Friction segment 137: Pad groove
137a: inlet portion 137b: outlet portion
137c:

Claims (8)

An annular core plate,
And a plurality of friction segments provided on the core plate at regular intervals,
The core plate and the friction segment facing the separate plate are formed with recessed pad grooves on the outer surfaces of the core plate and the friction segment to connect the inner circumferential surface and the outer circumferential surface of the core plate,
Wherein the pad groove is formed with a diffusion part extending in the rotational direction of the core plate, and the pad groove is asymmetrical.
2. The pad according to claim 1,
An inlet portion extending from the inner circumferential surface of the core plate,
An outlet portion connected to the inlet portion and enlarged toward an outer circumferential surface of the core plate,
And a diffusion portion connected to the outlet portion and extending along the rotational direction of the core plate to widen the outlet portion.
3. The friction pad of claim 2, wherein the diffusing portion extends linearly from the inlet portion, and the angle between the inlet portion and the diffusing portion is 140 deg. To 145 deg.
The friction pad for a wet clutch according to claim 2, wherein the diffusion portion extends in a curved shape from the inlet portion, and an angle between imaginary extension lines connecting the inlet portion and the diffusion portion is in a range of 135 to 140 degrees.
2. The friction pad of claim 1, wherein the pad groove is recessed through the friction segment to the outer surface of the core plate.
A clutch housing,
A piston mounted in the clutch housing and receiving a pressure of the transmission oil;
A clutch hub disposed in the clutch housing and mounted to the output shaft,
A plurality of separate plates connected to the clutch hub to receive a pressure from the piston,
And a clutch plate having friction pads alternately arranged with the separate plates,
And a pad groove connecting the inner circumferential surface and the outer circumferential surface of the friction pad is formed on the outer surface of the friction pad,
Wherein the pad groove is formed with a diffusion portion extending in the rotational direction of the friction pad, and the pad groove is asymmetric.
7. The pad according to claim 6,
An inlet portion extending from an inner circumferential surface of the friction pad,
An outlet portion connected to the inlet portion and enlarged toward the outer peripheral surface of the friction pad,
And a diffusion portion connected to the outlet portion and extending along the rotational direction of the friction pad to widen the outlet portion.
The wet type multiplate clutch according to claim 6 or 7, wherein the diffusion portion extends linearly from the inlet portion, or the diffusion portion extends from the inlet portion in a curved shape.

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