WO2002021008A1

WO2002021008A1 - Low-noise centrifugal clutch

Info

Publication number: WO2002021008A1
Application number: PCT/EP2000/008635
Authority: WO
Inventors: Bernd Oesterle; Gerhard Stoll; Klaus Langhans
Original assignee: Andreas Stihl Ag & Co.
Priority date: 2000-09-05
Filing date: 2000-09-05
Publication date: 2002-03-14

Abstract

The invention relates to a centrifugal clutch (1) comprising centrifugal bodies (3), consisting of clutch jaws (2), which are retained in a mobile manner on a support disc (5) on the drive side of the centrifugal clutch (1) by means of a retaining foot (4). The aim of the invention is to minimise the operating noise of the centrifugal clutch, which is caused by the knocking movements of the centrifugal bodies in the centrifugal clutch. To achieve this, the centrifugal bodies (3) are axially pre-tensioned against the support disc (5) by at least one spring element (10).

Description

Quiet body clutch

The invention relates to a centrifugal body clutch according to the preamble of claim 1.

Centrifugal body clutches are speed-actuated clutches with centrifugal bodies arranged radially movably on the drive side, which under the influence of centrifugal force on the output side of the centrifugal body clutch transmit a certain torque with the required contact force. After reaching a certain limit speed, the centrifugal body clutch engages automatically and enables the drive machines equipped with it to be started without load. Centrifugal clutches are advantageously used in high-speed drive machines such as internal combustion engines and enable a high starting torque to accelerate large masses in relation to the drive power, so that the drive machine does not have to be designed for a briefly high start-up power. In addition, centrifugal body clutches protect the drive machines against overloads and disengage the load in the lower speed range, for example at idling speed.

US 4,106,605 describes a centrifugal body clutch with centrifugal bodies, consisting of arcuate clutch shoes with a holding foot on each coupling jaw for pivotally mounting the centrifugal bodies on a carrier disk on the drive side of the centrifugal body clutch. The centrifugal bodies are pivotally supported by a bearing pin, which is parallel to an axis of rotation of the carrier disc and is evenly spaced apart on the carrier disc is arranged. If the carrier disc is driven in rotation, the centrifugal bodies swivel out under the action of the centrifugal force around the bearing bolts. On the driven side of the centrifugal body clutch, a clutch drum is arranged coaxially to the carrier disk, which surrounds the clutch shoes. The clutch jaws can be moved radially by the centrifugal force against the restoring force of a tension spring acting on the respective centrifugal body and can be pressed against the jacket of the clutch drum. Above a certain speed, the centrifugal force exceeds the restoring force of the tension spring, which causes the clutch drum to be frictionally entrained by the clutch shoes.

In practice, knocking or bell noises occur in centrifugal clutches, which lead to considerable noise pollution.

The invention is based on the object of developing a generic centrifugal body coupling in such a way that low-noise operation is made possible by the centrifugal body coupling.

This object is achieved with the features of claim 1.

In the centrifugal body coupling according to the invention, in order to prevent the axial and bending vibrations mentioned, the centrifugal body is provided in the centrifugal body coupling, axially biasing the centrifugal body against the carrier disk at least by means of a spring element. A permanent axial prestressing of the centrifugal bodies can be provided in various structural configurations depending on the type of storage of the centrifugal bodies. The centrifugal bodies are preferably with the help of bearing bolts, which are the holding foot reach through the centrifugal body, held pivotably on the support plate of the centrifugal body coupling. It may be expedient, for example, to hold the centrifugal bodies radially displaceably on the carrier disk for the transmission of high torques, for which purpose, for example, longitudinal guides between the holding feet of the centrifugal bodies and the carrier disk serve. In the case of a pivotable mounting of the centrifugal bodies on the carrier disk, it is expedient to arrange a spring element for axially prestressing the centrifugal bodies at least on the side of the centrifugal bodies facing away from the carrier disk. The spring element is advantageously of point symmetry and is arranged coaxially with the bearing bolts or with the axis of rotation of the carrier disk. The centrifugal bodies are axially biased against the bearing bolts or on the axis of rotation of the carrier disk.

It may be expedient to axially pretension the centrifugal bodies at a radial distance from the axis of rotation of the carrier disk, preferably in the vicinity of the coupling jaws, of the centrifugal bodies with the aid of one or more spring elements. For this purpose, the spring element is designed as a plate spring, preferably with radially extending slots arranged over its circumference. This constructive measure particularly effectively prevents the centrifugal bodies from tipping in the axial direction of the axis of rotation of the carrier disk and prevents the occurrence of noise caused by any striking movements of the centrifugal bodies in the centrifugal body coupling. It may be appropriate to design the spring element instead of as a plate spring in the form of a cover plate for the centrifugal bodies. The cover plate radially covers the coupling jaws of the centrifugal bodies. For the axial, resilient preloading of the centrifugal bodies, it is expedient to provide tongues which are notched out of the contour of the cover plate. Such tongue-like, resilient elements are preferably in the Arranged near the bearing bolts with the same radial distance from them and act on the holding feet of the centrifugal bodies

105 a. It can also be expedient to bring the resilient elements notched out of the contour of the cover disk into contact with the centrifugal bodies in the vicinity of the clutch shoes. It can also be expedient, in particular if the support disk, due to its shape, can be axially

110 the centrifugal body would not be suitable for attaching a cover plate with resilient elements arranged on the side of the centrifugal body facing away and / or facing the carrier plate. In this way, the centrifugal bodies are covered on both sides with the cover disks.

115

Embodiments of the invention are explained below with reference to the drawings. Show it:

1 is an exploded view of a centrifugal body clutch according to the invention,

2 shows a longitudinal section through the centrifugal body clutch in FIG. 1,

125 FIG. 3 shows a further longitudinal section through the centrifugal body clutch in FIG. 1,

4 shows a detail A in FIG. 3,

5 is a plan view of a cover plate with spring elements in FIG. 1,

6 shows a detail B in FIG. 5,

135 FIG. 7 shows a longitudinal section along the line VV in FIG. 5, 8 shows a longitudinal section along the line VI-VI in FIGS. 6, 140

Fig. 9 is a perspective view of a carrier disc with three centrifugal bodies, i Fig. 10 is a perspective view of the carrier disc

145 and centrifugal bodies from the opposite direction as in FIG. 9,

11 is an exploded view of the carrier plate with spring element in FIG. 10,

150

11a is a view of a carrier disk,

11b shows a cross section along the line VI-VI in Fig. 11a,

155

11c shows a detail from FIG. 11a,

12 shows a further exemplary embodiment of a carrier disk with centrifugal bodies,

160

13 shows a further exemplary embodiment of a carrier disk with centrifugal bodies,

14 a spring element,

165

15 is a plan view of a plate spring,

16 is a perspective view of the plate spring in FIG. 15,

170 17 shows a cross section through the plate spring in FIG. 15.

Fig. 1 shows an exploded view of a centrifugal body coupling 1 and its essential components. The

175 drive side of the centrifugal body clutch 1 is expediently formed from two centrifugal bodies 3 with advantageous _' circular arc-shaped clutch shoes 2. The centrifugal bodies 3 are each with a holding foot 4 on a carrier disk 5, which in the exemplary embodiment shown as a combined pole

180 rad / fan wheel is designed for an internal combustion engine, not shown, pivotally held. The carrier disk 5 rotates about an axis of rotation 11 during operation of the centrifugal body clutch 1.

185 The centrifugal bodies 3 are each configured identically and are spaced apart from one another point-symmetrically to the axis of rotation 11 of the carrier disk 5. The pivotable mounting and fastening of the centrifugal bodies 3 to the carrier disk 5 is carried out by means of bearing bolts 12 which,

190 opposite, parallel to the axis of rotation 11 on the support plate 5 and each pass through a bearing eye 23 in the holding foot 4 of the centrifugal body 3. For attachment to the carrier disk 5, the bearing bolts 12 can be provided with an external thread, for example, and

195 threaded blind holes 24 are screwed into the carrier plate 5 for the pivotable fastening of the centrifugal bodies 3.

In order to fasten the centrifugal bodies 3 to the carrier disk 5 in such a way that their free pivotability is not hindered, spacing means, such as flange bushings 25, can be provided in the bearing eyes 23 which slightly exceed the axial length of the bearing eyes. 3 and 4 show, the collar bushings 25 pull through the bearing eyes 23 and zen- 205, with their collar 26, radially adjoin the disks 17. The disks 17 are arranged coaxially with the axis of rotation 11 of the carrier disk 5. This constructive measure is a bracing of the bearing pin 12 to hold the disks 17 and the centrifugal body 3 on the

210 carrier disc 5 allows. However, the jam

Frets 26 of the bearing bolts 12 do not hold the support feet 4 of the centrifugal bodies 3, so that pivoting mobility of the centrifugal bodies 3 is maintained.

215 If the carrier disc 5 is driven in a rotating manner, the coupling jaws 2 are moved radially outward by the pivoting movement of the centrifugal bodies 3 under the action of the centrifugal force and pressed against the jacket 9 of a clutch drum 6 for rotary entrainment. At low speeds and

220 thus low centrifugal force, the centrifugal bodies 3 are held by a tension spring 8 in the pivoted-in position shown in FIGS. 1 and 2. The tension spring 8 is designed in the exemplary embodiment shown as a helical spring with end-side hooks 27. The hooks 27 engage in one

225 hook eye 28 at the bottom of the coupling jaws 2. The hook eyes 28 are arranged so that the tension spring 8 extends centrally between the bearing eyes 23. Oval cutouts 29 in the disks 17 designed as deep-drawn sheet metal parts are dimensioned such that the cutouts 29 prevent the tensile

230 of 8 surrounded by a distance. At the same radial distance y from the center point of a through-hole 30 for the bearing bolts in the disks 17, three spring elements 10 are arranged as elements 18 which are disengaged like tongues from the disk 17 (cf. FIGS. 1, 5 and 6). The spring elements 10 tension 35 in the assembled state of the centrifugal body clutch 1

Centrifugal body 3, in particular the holding feet 4 axially against the carrier disc 5 and permanently prevent that even with a

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340 to avoid cracks in the plate spring 14, which is preferably made of spring steel. The circumferential edge 15 of the plate spring 14 is provided with a flat circular disk-shaped surface 38 which lies radially in the vicinity of the coupling jaws on the holding feet of the centrifugal bodies

345 is coming. A hexagonal opening in the center of the plate spring serves for the positive, rotationally secured mounting of the TelTer spring on the hexagon 39 in FIG. 11 or 12. The plate spring 14 is essentially flat and bell-shaped in its cross section, as shown in FIG. 17

350 clarifies. The plate spring 14 is arranged on its side of the centrifugal body facing away from the carrier disk 5 or steel disk 19. As FIGS. 12 and 13 show in a plan view of further arrangements of carrier disks 5 and centrifugal bodies 3, the carrier disk 5 can be designed as three

355 angularly jagged structures (FIG. 12) or as disks with tangentially projecting holding arms 20 (FIG. 13).

Claims

Expectations

1. centrifugal body clutch with a centrifugal body (3) and a clutch shoe (2), which with a holding foot (4)

360 on a carrier disc (5) on the drive side of the

Centrifugal body clutch (1) is movably held and with a coaxially to the axis of rotation (11) of the carrier plate (5) on the output side of the centrifugal body clutch (1) arranged Kup drum (6), the

365 clutch drum (6) engages over the clutch shoe (2) and the clutch shoe (2) can be placed against the jacket (9) of the clutch drum (6) during operation of the centrifugal body clutch (1) under the action of centrifugal force against a restoring force (7),

370 characterized in that the centrifugal body (3) is biased axially against the carrier disc (5) by at least one spring element (10).

2. centrifugal body clutch according to claim 1,

375 characterized in that the centrifugal body (3) is pivotably held on the carrier disc (5) by means of a bearing pin (12).

3. centrifugal body clutch according to claim 1,

380 characterized in that the centrifugal body (3) is held radially displaceably on guides (13) of the carrier disk (5).

4. centrifugal body coupling according to one of claims 1 to 3, 385 characterized in that the spring element (10) is held coaxially to the bearing pin (12) or to the axis of rotation (11) of the carrier disc (5) and the centrifugal body (3) on the Bearing pin (12) or the rotary Axis (11) of the carrier disc (5) axially prestressed

390

5. centrifugal body coupling according to one of claims 1 to 3, characterized in that the centrifugal body (3) of the spring element (10) at a radial distance from the bearing pin (12) or the axis of rotation (11) of the carrier

395 washer (5), preferably in the vicinity of the clutch shoes (2), is axially preloaded.

6. centrifugal body coupling according to one of claims 1 to 5, characterized in that the spring element (10)

400 plate spring (14), preferably with radial slots (16) arranged over its circumference (15).

7. centrifugal body coupling according to one of claims 1 to 5, characterized in that the spring element (10)

405 is formed by a tongue (18) notched out from the contour of a disk (17).

8. centrifugal body coupling according to one of claims 1 to 5, characterized in that the carrier disc (5) as

410 steel disc (19) is formed with a number of radial holding arms (20) corresponding to the number of centrifugal bodies (3).

9. centrifugal body clutch according to claim 7 and 8,

415 characterized in that the spring element (10) designed as a disk (17) and the carrier disk (5) extend as far as the coupling jaw (2).

10. centrifugal body coupling according to one of claims 1 to 9, 420 characterized in that the spring element (10) on the side of the carrier plate (5) facing away (21) of the Centrifugal body (3) is arranged.

11. centrifugal body coupling according to one of claims 1 to 9, 425 characterized in that a spring element (10) is arranged on both axial sides (21, 22) of a centrifugal body (3).