GB2155566A

GB2155566A - Clutch diaphragm spring having cooling vanes

Info

Publication number: GB2155566A
Application number: GB08505007A
Authority: GB
Inventors: Heiji Fukutake
Original assignee: Exedy Corp; Daikin Manufacturing Co Ltd
Current assignee: Exedy Corp
Priority date: 1984-03-09
Filing date: 1985-02-27
Publication date: 1985-09-25
Also published as: FR2560951A1; JPS60145625U; KR870001178B1; DE3508167A1; KR850006582A; GB8505007D0

Abstract

The diaphragm spring 6 is provided with radially extending tongues 17, portions of the tongues 17 radially outward of contact portions 23 for the release bearing 8 being partially bent to form vanes 25 for taking in a cool air, so that the cool air from an exterior space in which the release bearing 8 is disposed is drawn by the vanes 25 into an interior space in which the clutch facing is disposed. <IMAGE>

Description

SPECIFICATION Clutch This invention relates to a clutch, more particularly but not exclusively the friction, diaphragm spring type for automobiles.

Generally, in a friction clutch, a friction facing provided on a clutch disc is adapted to be pressed by a pressure plate onto a flywheel. Therefore, the temperature of said facing unavoidably increases so that abnormal wear and/or seizure may occur on the facing.

Especially, in a conventional clutch of the diaphragm spring type, wherein the diaphragm spring is employed to force the pressure plate toward the flywheel, the diaphragm spring operates to close the rear side (opposite to the fiywheel) of the space in which the facing is disposed, so that the temperatures in the space may rapidly increase, and thus, above problem becomes pronounced.

Accordingly, it is an object of the present invention to provide an improved clutch, overcoming the above-noted problems.

With this object in view the present invention provides a clutch comprising a flywheel forming input means, a friction facing forming output means, a pressure plate for pressing the friction facing against the flywheel, a diaphragm spring disposed at the rear side of the pressure plate for forcing the pressure plate toward the fly-wheel and a release bearing disposed adjacent to the radially inner portion of the diaphragm spring and opposite to the pressure plate for forcing the radially inner portion of the diaphragm spring, siad diaphragm spring being provided at the radially outer portion with an annular portion seated on the pressure plate and radially extending tongues extending continuously to the inner periphery of the annular portion, and the tongues being provided at radially inner ends with contact portions to which the release bearing is adapted to contact, characterised in that portions of the tongues radially outside the contact portions for the release bearing are partially bent to form vanes which project oppositely to the flywheel for taking in cool air, so that the cool air in an exterior space in which the release bearing is disposed may be supplied by the vanes into an interior space in which the facing is disposed.

The invention will be described further, by way of example, with reference to the accompariying drawings in which: Figure 1 is a fragmentary schematic sectional view of a preferred embodiment of the clutch of the invention; Figure 2 is a fragmentary schematic sectional vein taken along lines ll-ll in Fig. 1; Figure 3 is a fragmentary schematic sectional view taken along line Ill-Ill in Fig. 2; Figure 4 is a fragmentary schematic perspective view of a spring of the embodiment of Fig. 1; Figure 5 is a fragmentary schematic perspective view of a known diaphragm spring; and Figure 6 is a fragmentary schematic sectional view of another known diaphragm spring.

As can be seen in Fig. 1, the preferred clutch comprises a friction facing 3 positioned between a flywheel 1 of an engine and an annular pressure plate 2. The facing 3 is fixed to an outer peripheral portion of a clutch disc 5 connected to an output shaft 4 (only a centre line thereof is illustrated). When the pressure plate 2 presses the facing 3 onto the flywheel 1, the clutch engages and a torque is transmitted from the flywheel 1 through the disc 5 to the output shaft 4. A diaphragm spring 6 for forcing the pressure plate 2 toward the facing 3 is disposed at the rear of the pressure plate 2 opposite to the disc 5.

The outer peripheral portion of the spring 6 is seated on a projection 7 on the rear surface of the pressure plate 2. A release bearing 8 is disposed adjacent to the inner periphery of the spring 6 and opposite to the disc 5. The release bearing 8 is connected to a known clutch operation mechanism (not shown) including a clutch pedal.

The outer periphery and the rear surface of the spring 6 are covered by a clutch cover 1 0.

The clutch cover 10 includes a substantially annular end wall 11 and a cylindrical peripheral wall 1 2 which inclines and projects from the outer periphery of the end wall 11 toward the flywheel 1 and is fixed at the end thereof to the flywheel 1. Circumferentially spaced axial pins 1 3 are fixed at their ends to the inner peripheral portion of the end wall 11.

The pins 1 3 extend from the end wall 11 through recesses 1 5 of the spring 6 toward the pressure plate 2, and are provided at the other ends with enlarged ends 1 4 positioning between the pressure plate 2 and the spring 6, respectively.

A pair of wire rings 1 9 and 20 are disposed at the outside, in the radial direction of the spring 6, of the pins 13. The pins 13 are employed to support the radially inner peripheries of the wire rings 1 9 and 20, and the rings 1 9 and 20 form fulcrums for the spring 6. The wire ring 1 9 is disposed between the spring 6 and the wall 11, and the wire ring 20 is disposed between the spring 6 and the ends 14 of the pins 13.

As illustrated in Fig. 2, the spring 6 is provided at the radially outer portion with a continuous annular portion 16, of which an outer peripheral portion is seated on the pressure plate 2 (Fig. 1). The spring 6 is also provided with slits 1 8 which extend radially from the inner periphery to the radially middle of the spring 6. Thus, the radially inner and middle portion of the spring 6 is divided by the slits 1 8 to form radially extending tongues 1 7. Said recesses 1 5 through which said pins 1 3 extend are formed by portions of the slits 1 8 which are adjacent to the annular portion 6 and are circumferentially enlarged.Contact portions 23, which said release bearing 8 contacts, are formed at the radially inner ends of the tongues 1 7.

Referring to Figs. 3 and 4, it will be seen therefrom that both side edge portions of each tongue 17, which extend substantially in the radial direction of the spring and are positioned between the contact portion 23 and the recess 15, are bent to form a vane 25 for taking in a cool air and a vane 26 for guiding the cool air. As illustrated more particularly in Fig. 3, the vanes 25 incline and project from the bodies of the tongues 1 7 toward the release bearing 8 and in a direction which is the same as its rotation direction R. The vanes 26 incline and project from the bodies of the tongues 1 7 toward the pressure plate 2 and in a direction opposite to the rotation direction R.The vanes 25 and 26 are provided at the forward side and the rearward side respectively of the individual tongues 1 7 with respect to the rotation direction R so that the vanes 25 and 26 are disposed alternately in the circumferential direction of the spring 6.

As illustrated more clearly in Fig. 4, the vanes 25 and 26 do not extend to the contact portions 23 of the tongues 1 7 so that the interference of the vane 25 and the release bearing 8 may be prevented. However, of necessary the vanes 26 may be provided at the contact portions 23.

The operation of the preferred clutch is as follows. When the clutch is operated to disengage, the release bearing 8 pushes the contact portions 23 of the spring 6 to deform the spring 6 into a shape indicated in outline 6a in Fig. 1, so that the pressing force to the pressure plate 2 by the spring 6 is released.

When the clutch is operated to engage, the pressing force by the release bearing 8 to the contact portions 23 is released, so that the spring 6 returns to its original shape as shown by a solid line and forces the pressure plate 2.

In this way the pressure plate 2 presses the facing 3 against the flywheel 1 to engage the clutch, and the torquf is transmitted from the flywheel 1 through the disc 5 to the output shaft 4.

Both in said engaged and disengaged conditions, the clutch cover 10 rotates together with the flywheel 1, and thus, the spring 6 always rotates together with the flywheel 1.

Therefore, the cool air in an exterior space 27 in which the release bearing 8 is disposed is supplied by the vanes 25 and 26 into an interior space 28 in which the facing 3 and the pressure plate 2 are disposed, and this supplied air cools the facing 3, flywheel 1 and pressure plate 2.

According to the present invention, as stated hereinbefore, since the diaphragm spring 6 is provided with vanes 25 for supplying the cool air from the exterior space 27 into the interior space 28, the surfaces for the frictional engagement of the facing 3 and others are sufficiently cooled, so that the abnormal wear and seizure of the facing 3 can be prevented and the durability thereof is improved. Further, since the vanes 25 are formed by bending the spring 6, the structure can be simple and inexpensive, as compared with a structure including separate or independent vanes.

Further, the bent vanes 25 and 26 can increase the strength of the tongues 1 7 of the spring 6. For reference, Figs. 5 and 6 illustrate some conventional diaphragm springs which have tongues which have one or both sides bent substantially perpendicular toward a clutch disc (oppositely to a release bearing) for merely increasing the spring's strength.

However, these known springs having only inwardly bent vanes cannot supply cool air toward the facing for cooling it.

In the present invention, the vanes 26 for guiding the air may be eliminated. The vanes 25 and 26 may be provided only at some of the tongues 1 7. A circumferentially middle portion between both side edges of the tongue may be partially cut and bent to from the vane.

Although the invention has been described in its preferred form with a certain degree of particularity, it should be understood that the present disclosure of the preferred form may be changed in the details of construction, and the combination and arrangement of parts may be altered without departing from the scope of the invention as hereinafter claimed.

Claims

1. A clutch comprising a flywheel forming input means, a friction facing forming output means, a pressure plate for pressing the friction facing against the flywheel, a diaphragm spring disposed at the rear side of the pressure plate for forcing the pressure plate toward the flywheel, and a release bearing disposed adjacent to the radially inner portion of the diaphragm spring and opposite to the pressure plate for forcing the radially inner portion of the diaphragm spring, said diaphragm spring being provided at the radially outer portion with an annular portion seated on the pressure plate and radially extending tongues extending continuously to the inner periphery of the annular portion, and the tongues being provided at radially inner ends with contact portions to which the release bearing is adapted to contact, characterised in that portions of the tongues radially outside the contact portions for the release bearing are partially bent to form vanes which project oppositely to the flywheel for taking in cool air, so that the cool air in an exterior space in which the release bearing is disposed may be supplied by the vanes into an interior space in which the facing is disposed.

2. A clutch as claimed in claim 1 or 2 wherein said vanes for taking in cool air are provided at forward side portions of the tongues with respect to the rotating direction of the diaphragm spring.

3. A clutch as claimed in claim 1 or 3 wherein said tongues are partially bent toward the flywheel to form vanes for guiding the cool air.

4. A clutch as claimed in claim 3 wherein said vanes for taking in the air is formed at forward side portions of the respective tongues which extend substantially radial direction of the spring and are positioned forward to bodies of the tongues in the circumferential direction of the spring, and said vanes for guiding the air are formed at other side portions of the respective tongues, so that the vanes for taking in and guiding the air may be disposed alternately in the rotating direction of the spring.

5. A clutch as claimed in any preceding claim wherein said clutch is a friction, diaphragm spring type.

6. A clutch substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4 of the accompanying drawings.