JPH04347046A - Fluid transmission device with lockup clutch - Google Patents

Abstract

PURPOSE:To make the surface pressure of the engaging surface of a lockup clutch with a front cover constant in a lockup operation, in a fluid transmission device with the lockup clutch. CONSTITUTION:In a fluid transmission device with a lockup clutch, a lockup clutch disk 18 which is engaged with or released from a front cover 3 and combined to a turbine runner 13 is provided. A lining element 24 is provided to the lockup clutch disk 18 at the engaging surface with the front cover 3. The lockup clutch disk 18 provided with a curved surface to generate almost uniform pressing force to the engaging surface between the lockup clutch disk 18 and the front cover 3 through the lining element 24 in the lockup operation is provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid transmission device with a lock-up clutch incorporated in a drive transmission system of a vehicle such as an automobile, and more particularly to an engagement surface of a lock-up clutch.

0002

[Prior Art] In general, fluid transmission devices such as torque converters and fluid couplings that transmit power from internal combustion engines etc. through fluid have better absorption of torsional vibration and shock than mechanical couplings. On the other hand, it has the disadvantage that the transmission efficiency decreases when the driving side rotational speed and the driven side rotational speed become close to each other. Therefore, in order to deal with the above-mentioned drawbacks, fluid transmission devices with a so-called lock-up clutch, which mechanically directly connects the driving side and the driven side, have been put into practical use in the rotation range where the transmission efficiency decreases. For torque converters used in transmissions, there is a growing trend to adopt torque converters with lock-up clutches with the main aim of improving fuel efficiency.

[0003] Conventionally, as a torque converter equipped with this type of lock-up clutch, for example, the
There is one described in Japanese Patent No. 6259, and it is shown as shown in FIG. In FIG. 4, a lockup piston 101 immersed in hydraulic oil in a fluid transmission device 100 moves the outer circumferential surface of a clutch hub 102 in the axial direction according to the oil pressure difference before and after the piston (the difference between oil pressures P1 and P2 in the figure). When converter cover 1 slides and the oil pressure difference becomes extremely large, that is, when P2 is drained due to lock-up selection, converter cover 1
Clutch facing 10 installed inside 04
3 frictionally engages with the lockup piston 101 and rotates together with the converter cover 104. The rotation of the clutch facing 103 is transmitted to the input shaft of the transmission via the clutch hub 102 after the engagement shock, engine torque fluctuation, etc. are absorbed by the torsion damper 105. That is, the clutch facing 103 of the converter cover 104 and the lockup piston 10
1, a direct mechanical connection between the converter cover 104 and the turbine runner 107 is achieved, eliminating loss in transmission efficiency due to slip between the pump impeller 106 and the turbine runner 107, increasing transmission efficiency and improving fuel efficiency. This will lead to improvements in

0004

[Problem to be Solved] However, in such a conventional fluid transmission device with a lock-up clutch, stress deformation occurs in the lock-up piston 101 due to hydraulic load on the lock-up piston 101 during lock-up operation, and this Due to the deformation, when the lockup piston 101 and the clutch facing 103 engage, the surface pressure on the engagement surfaces becomes uneven, which may cause uneven wear of the clutch facing 103. To explain this in detail, when the lockup is activated, that is, when the lockup piston 101 is moved by sliding the outer peripheral surface of the clutch hub 102 toward the converter cover 104 side by hydraulic pressure, the lockup as shown by the arrow in FIG. 5 occurs. A hydraulic load of P1-P2, which is the difference between the hydraulic pressure P1 between the piston 101 and the turbine runner 107 and the hydraulic pressure P2 between the converter cover 104 and the lockup piston 101, is applied. The lockup piston 101 is bent in accordance with this load distribution, and the converter cover 10
4, the outer peripheral side of the lock-up piston 101 is engaged first. As a result, the surface pressure of the clutch facing 103 increases on the outer peripheral side, and there is a possibility that uneven wear of the clutch facing 103 may occur. The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to prevent uneven wear of the clutch facing by reducing the amount of displacement of the surface pressure of the friction engagement surface.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention takes the following measures. A lock-up clutch in which a pump impeller and a turbine runner are housed in a housing, and has a disc-shaped lock-up clutch disc that is engaged with a member integrally connected to the pump impeller via a lining element. In the fluid transmission device, the lining element is coupled to either the lock-up clutch disc or a member integrally connected to the pump impeller, and the lining element or the engagement A curved surface is provided on the outer peripheral side of the surface.

[0006]

[Operation] When the lockup is activated, when the lockup clutch disk is pressed by the lockup hydraulic pressure against the member that is integrally connected to the pump impeller, the pressure load on the outer circumference side is large, so the outer circumference side of the lockup clutch disk is pressed against the pump impeller. It deflects in the direction of the member that is integrally connected to the impeller. Therefore, since a curved surface is provided in advance on the engagement surface of the member that is integrally connected to the lock-up clutch disk or the pump impeller, on which the lining element is provided, the lock-up clutch disk and pump are connected via the lining element. The impeller and the member integrally connected can be engaged with a substantially uniform pressing load.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 1 is an input shaft,
It is rotated clockwise when viewed from the left side of FIG. 1 by an engine not shown in the figure. A front cover 3 is connected to the input shaft 1 and rotates together with the input shaft 1. The front cover 3 is connected to the peripheral edge of the pump impeller 5 at its peripheral edge. The pump impeller 5 is supported by a hollow shaft 6 concentric with the input shaft 1, and the hollow shaft 6 drives a hydraulic pump 7. The hollow shaft 6 is located around a sleeve 9 that is fixedly supported by a torque converter housing 8, and is rotatably supported by a hub portion 8a of the housing 8 via a bearing element 10.

[0008] An output shaft 11 is disposed concentrically with and passing through the interior of the hollow shaft 6. A turbine runner 13 disposed opposite the pump impeller 5 within a fluid chamber formed by the front cover 3 and the pump impeller 5 is connected to the output shaft 11 via a hub 14 in a torque transmitting relationship. A stator 15 is provided between the pump impeller 5 and the turbine runner 13 for guiding fluid flowing back from the turbine runner 13 to the pump impeller 5. The stator 15 is supported by a sleeve 9 via a one-way clutch 16. There is.

The hub 14 has a cylindrical outer circumferential surface 1 on its outer circumference.
4a is formed, and an annular lock-up clutch disc 1 disposed within the fluid chamber 12 is formed on the cylindrical outer peripheral surface 14a.
A cylindrical inner peripheral surface 18a provided along the inner periphery of 8 is slidably and rotatably engaged. An annular groove 20 is formed in the cylindrical outer peripheral surface 14a of the hub 14.
A seal ring 21 is fitted inside, and serves to maintain the seal between the cylindrical outer circumferential surface 14a of the hub 14 and the cylindrical inner circumferential surface 18a of the lock-up clutch disc 18. A piston-shaped outer circumferential surface 18d is formed on the outer circumference of the lock-up clutch disk 18.
d is disposed close to a cylindrical inner circumferential surface 3a formed on the peripheral edge of the front cover 3. Thus, the lock-up clutch disk 18 constitutes a piston that slides within an annular cylinder disposed between the cylindrical outer circumferential surface 14a of the hub 14 and the cylindrical inner circumferential surface 3a of the front cover 3. The lock-up clutch disk 18 has one end surface 18b.
When facing the inner end surface 3b of the front cover 3 and applying a predetermined hydraulic pressure to the other end surface 18c, the inner end surface 3b
is pressed against and frictionally engaged via the lining element 24.

A disk element 26 is further secured to the hub 14 by a pin 25. An annular disk element 27 is disposed on the peripheral edge of the disk element 26 opposite to it, and these two disk elements 26 and 27 are connected to each other by pins 28 spaced apart along the peripheral edge. There is. Between these disk elements 26 and 27, another annular disk element 29 is arranged so as to be rotatable relative to the disk elements 26, 27 and the pin 28 connecting them. The disk element 29 is connected at its outer periphery to the outer periphery of the lock-up clutch disk 18, particularly in a torque transmitting relationship. disk element 2
A plurality of compression coil springs 30 are provided between the disk element 29 and the disk element 29 and spaced apart along their peripheries.

FIG. 2 shows the annular engagement surface between the lock-up clutch disc 18 and the inner end surface 3b of the front cover.
The inner end surface 18b is a curved surface such that the gap with the lining element 24 increases toward the outer and inner circumferences. Next, the effect will be explained. In the fluid transmission device with a lockup clutch shown in FIG. 1, when the lockup clutch is to be operated, hydraulic pressure is supplied through the oil passage 32, and the hydraulic pressure is introduced toward the fluid chamber 12 from the root of the stator. . As a result, the lock-up clutch disk 18 is pressed toward the inner end surface of the front cover 3 and frictionally engages with the front cover 3 via the lining element 24. At this time, the lock-up clutch disk 18 is actually
A large amount of oil pressure is applied to the outer peripheral side of the end surface 18b, and the oil pressure is applied unevenly. Therefore, when lock-up is activated,
Since the hydraulic pressure exerted on the lockup clutch disk 18 is large on the outer circumferential side, the outer circumferential side of the lockup clutch disk 18 is directed toward the front cover 3, that is, the lockup clutch disk 18 is directed toward the front cover relative to the virtual plane including the line orthogonal to the axis. bend to the side.

At this time, since a curved surface is provided on the outer peripheral side of the lock-up clutch disc 18 at the engagement surface between the lock-up clutch disc 18 and the front cover 3 via the lining element 24, the lining element 24 is bent. and makes intimate contact with the entire engagement surface. Therefore, substantially uniform pressing stress is generated over the entire area of the engagement surface, and uneven wear can be prevented. After the lockup operation, that is, after the lockup clutch is engaged, the hydraulic load applied to the lockup clutch disc 18 becomes constant. The inner circumferential side of the lockup clutch disk 18 slides on the sliding surface of the hub 14, using the engagement surface between the lockup clutch disk 18 and the front cover 3 as a fulcrum. Therefore, the inner peripheral side of the lock-up clutch disk 18 is bent toward the front cover 3 using the above-mentioned fulcrum as a support point. At this time, since a curved surface is also provided on the inner peripheral side of the engagement surface of the lock-up clutch disc 18, the lining element 24 is bent and comes into close contact with the entire engagement surface. Therefore, even after engagement, a substantially uniform pressing force is generated over the entire area of the engagement surface, and uneven wear can be prevented. That is, even during and after engagement, a uniform pressing force can be generated on the engagement surface, and the lining element 2
4. Uneven wear can be prevented and durability can be improved. Further, since the surface pressure is made uniform, the effective radius of the lining element 24 can be secured, and the maximum transmission torque capacity can be secured. Furthermore, since the generation of high surface pressure can be suppressed by equalizing the surface pressure, the difference between the static friction coefficient μ0 and the dynamic friction coefficient μD can be reduced, and self-excited vibration when the lining element 24 is engaged can be suppressed, reducing judder. can be prevented from occurring.

[0013] Torque is transmitted from the input shaft 1 to the front cover 3, the lock-up clutch disc 18, and the disc element 2.
9, compression coil spring 30, disk elements 26 and 27,
It is mechanically transmitted to the output shaft 11 via the hub 14. When the torque suddenly increases during the torque transmission process, the compression coil spring 30 is temporarily greatly compressed, and has a buffering effect that absorbs the sudden increase in torque and prevents an impact change from occurring in the torque transmission. conduct. Hydraulic pressure is oil line 33
When hydraulic pressure is supplied between the front cover 3 and the clutch disc 18 via the groove 34 formed in the output shaft 11, the chamber 35, and the groove 37 of the washer 36, the lock-up clutch disc 18 is driven in a direction away from the front cover 3, the engagement between the lock-up clutch disc 18 and the lining element 24 is released, and the rotational power is transmitted from the input shaft 1 to the output shaft 11 by the pump impeller 5 and the turbine. This is carried out via a fluid transmission device consisting of a runner 13 and a stator 15.

FIG. 3 shows a second embodiment of the invention. Figure 3
The second embodiment shows an annular engagement surface between the lock-up clutch disk 18 and the inner end surface 3b of the front cover. The difference from the first embodiment described above is that a curved surface is provided so that the gap between the inner end surface 3b of the front cover 3 that joins the lining element 24 and the lining element 24 increases as it goes toward the outer and inner circumferential sides. ing. The lining element 24 is provided with a spring 41 that prevents the lining element 24 from being dragged or dragged by the lock-up clutch 18 when engaged. The rest of the structure is the same as that of the first embodiment described above, and the same or corresponding parts are denoted by the same reference numerals. Incidentally, this second embodiment can also obtain the same functions and effects as the first embodiment.

Although the present invention has been described above with reference to specific embodiments illustrated, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is. For example, the spring 41 that prevents the lining element 24 from dragging or twisting in the second embodiment described above can also be applied to the first embodiment. Furthermore, in each of the embodiments described above, the engaging surface of the front cover 3 or the lock-up clutch disc 18 is provided with a curved surface.
The lining element may also be provided with a curved surface.

[0016]

[Effects of the Invention] When the lockup is activated, even if the lockup clutch disk is pressed by an uneven hydraulic load and undergoes stress deformation, the lockup clutch disk and pump impeller are integrally connected via the lining element. Since at least one of the members has been modified to have a curved surface, the member can be engaged with a uniform pressing load. Therefore, uneven wear of the lining element can be prevented and the durability of the lining element can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fluid transmission device with a lock-up clutch showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a first embodiment of the lock-up clutch disc.

FIG. 3 is a sectional view showing a second embodiment of the lock-up clutch disc.

[Figure 4] Conventional fluid transmission device with lock-up clutch

[Figure 5] Hydraulic pressure load distribution applied to the lock-up clutch disc

[Explanation of symbols]

3...Front cover 5...Pump impeller 8...Housing 13...Turbine runner 18...Lock-up clutch board 24... Lining element

Claims (1)

[Claims] Claim 1: A disk-shaped lock-up clutch disc in which a pump impeller and a turbine runner are housed in a housing, and which is engaged with a member integrally connected to the pump impeller via a lining element. In the fluid transmission device with a lock-up clutch, the lining element is coupled to either the lock-up clutch disk or a member integrally connected to the pump impeller, and at an outer peripheral portion near the coupling portion, A fluid transmission device with a lock-up clutch, characterized in that a curved surface is provided on the outer peripheral side of a lining element or an engagement surface.