GB2117067A

GB2117067A - Synchronizer device

Info

Publication number: GB2117067A
Application number: GB08306730A
Authority: GB
Inventors: Walter Griesser
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1982-03-12
Filing date: 1983-03-11
Publication date: 1983-10-05
Also published as: GB8306730D0; DE3208979A1; IT8319730A0; IT1161906B; BR8301241A

Abstract

Synchronizing/baulking rings (12, 22) in a change-speed gear are coupled with angular lost-motion to shift sleeve carrier (4) via lugs (15, 25) cooperable with spring buffers (6, 7) located at the sides of recesses (41, 410) in the carrier. The buffers may be dished spring washers (62, 64) or H- section members with resilient pads. As a result of the buffers the disadvantageous effects of rotary vibrations are opposed in the case of non-initiated as well as initiated synchronizer processes, whilst hard shocks and therefore damage are avoided and rotary vibrations absorbed, and premature unlocking as a result of hard shocks originating from rotary vibrations is also prevented. <IMAGE>

Description

SPECIFICATION Synchronizer device This invention relates to a synchronizer device for positively connected shift clutches of changespeed gears comprising an axially displaceable shift sleeve which is engageable in a clutch gear ring, a sleeve carrier disposed in a rotationally and axially fixed manner on a gear portion and supporting the shift sleeve and a friction ring formed as an engagement lock which, with rotary clearance, is in rotational connection with the sleeve carrier via rotary stops, in which springs are arranged between the sleeve carrier, in a recess in the latter, and a stop cam of the friction ring which projects into the said recess.

A synchronizer device of this type is known from German Patent Specification 2628039, in which the springs are designed to maintain the stop cams centrally in each case in the recess of the sleeve carrier, if the friction mechanism is not effective, in order to prevent rotary vibrations which could lead to damage or breakage of the rotary cams. In addition, hard shocks are dissipated in the case of rotary vibrations which arise. As a result of the necessary design with relatively soft springs, and taking into account the intensity of the rotary vibrations arising, it was not possible with a device of this type to maintain the stop cams in the central position of the recess and therefore to prevent the negative effects of rotary vibrations.The slight spring cushioning of the hard shocks from the rotary vibrations and therefore the damage to the stop cams of the friction ring and the rotary cams of the sleeve carrier cannot, therefore, be completely prevented.

An object of the invention is, therefore, in the case of a synchronizer device as set out above, to provide a drive device between the sleeve carrier and a friction ring which is not sensitive to rotary vibrations.

According to the invention, the rotary stops are disposed in the sleeve carrier and are formed by springs or spring mechanisms.

If the rotary stops in the recess of the sleeve carrier are themselves formed by springs or spring mechanisms, it is possible to use relatively strong springs which may be adjusted, in an optimum manner to the intensity of the rotary vibrations, without impairing the deflection of the friction ring into the locking position, as no obstructions have to be overcome, i.e. no spring tensions, from the stop cam of the friction ring up to the rotary stops.

Use may also be made of springs or spring mechanisms having a very strong absorption effect which also opposes the rotary vibrations.

Premature unlocking, which may lead to considerable damage, is not possible in the case of a synchronized friction ring which is moving into the locking position or is already in this position as a result of thrust forces triggered by rotary vibrations and hard shocks as all the shocks are adequately cushioned and absorbed.

In addition, the difficulty in shifting which often occurs during unlocking, and which takes place after synchronous running has been reached as a result of static friction between the parts to be unlocked in the rest condition, is opposed. In the case of the intermittent break-down of the friction moment between the friction surfaces on the friction ring and on the clutch body, the relatively strong spring is in a position to cause a micromovement of the stop, as a result of which the static friction also breaks down.

If the spring devices are formed by one or a plurality of cup springs, the spring path may be very short, which is important with respect to the rotary stops in connection with the deflection required for locking. However, very high spring forces may be obtained with a comparatively small spring path. Particularly good absorption may be obtained with more than one cup spring.

However, simple rubber or plastic springs (rubber buffered) disposed externally to the legs of a U-shaped spring-mounted sheet component, fulfil these conditions in an advantageous manner in a very simple and therefore economic embodiment.

Further details of the invention will be apparent from the following description of various embodiments; making reference to the accompanying drawings, in which: Figure 1, 1 A is a longitudinal cross section through a synchronizer device; Figure 2 is a partial cross section through a sleeve carrier; and Figure 3 is a partial cross section similar to that of Figure 2, but relating to a further embodiment.

The synchronizer device of Figures 1, 1 A represents two examples of a shift clutch, for convenience embodied in a composite drawing, each to enable, in a change-speed gear, the alternate engagement and disengagement at will of two gear wheels 1 and 2 from a gearshaft 3, the gear wheels being rotatably mounted on this gearshaft 3.

In this respect, each of the gear wheels 1, 2 is connected in a rotationally fixed manner with a clutch body 11, 21, with which an axially displaceable shift sleeve 5 may be engaged. The shift sleeve 5 is axially displaceable, although mounted in a rotationally fixed manner, on a sleeve carrier 4 which is disposed in a rotationally and axially fixed manner on the gearshaft 3.

Between the sleeve carrier 4 and the respective clutch bodies 11, 21 there are disposed friction rings 12, 22, provided with locking teeth 16, 26 acting as engagement locks, whose respective friction surfaces 13, 23 cooperate with corresponding counter-surfaces, in the form of the conical counter-surfaces 14, 24 on the clutch bodies 1 1,11, 21, asillustrated in the drawings. The friction rings 12, 22 are in rotary connection with respective stop cams 15, 25 disposed about the periphery and projecting axially into recesses 41 in the sleeve carrier 4, wherein spring devices 6, 7 disposed in the recess 41, on both sides of the stop cams 15, 25, form rotary stops 61, 71 and provide a predetermined rotary clearance which may be derived from the locking teeth.

In Figures 1 and 2, a recess 41 is shown in the sleeve carrier 4, together with a stop cam 1 5 of the friction ring 12 and with spring mechanisms 6, 6A, wherein the spring mechanism 6 is embodied with a cup spring 62 and the spring mechanism 6A with a plurality of cup springs which are guided with respect to their apertures 64 by thrust plungers 63, whilst the latter are guided in a longitudinally movable manner in bores 42, provided in the sleeve carrier 4 transverse to the recess 41.

Figures 1 A and 3 show a further embodiment.

A stop cam 25 of the friction ring 22 projects, as in Figure 2, into a recess 410 in the sleeve carrier 40. Rotary stops 71 are formed by a spring element 7 which is constituted by a U-shaped sheet component 72 which is bent and springmounted and has rubber or plastics buffers (rubber spring 75), for example vulcanised or adhered externally to its legs. In this way the spring element 7 may not only be clamped in the sleeve carrier 40, but also fastened, for example by adhesive. The length of the U-shaped spring element 7 corresponds approximately to the width of the sleeve carrier 40.

In the non-shifted condition, the stop cams 1 5, 25 may be completely freely adjusted as a result of the rotary gap between the rotary stops 61, 71 (Figures 2 and 3) with respect to the conditions in the synchronizer device, as determined by forces in the peripheral direction, tractive forces from the lubricating and cooling means and also from rotary vibrations. Abutment on the rotary stops takes place relatively gently as a result of the springing and absorption, and the absorption also contributes to attenuation of any vibrations which may be present.

If synchronized, the stop cam 1 5, 25 rotates, in accordance in each case with the rotary conditions of the gear wheels 1, 2 to be shifted and the shaft 3, in the direction of a rotary stop 61, 71, if it has not previously come into contact with the same rotary stop for the reasons described above.The forces acting in the direction of the rotary stop 61,71 are in this respect dependent on the friction moment at the friction surfaces 1 3, 14 or 23, 24. The springs 62, 75 or spring mechanisms 6, 6A, 7 are dimensioned such that the minimum and maximum springing of the rotary stops 61,71 lead in all cases to a reliable locking of the locking teeth 1 6, 26 which are disposed on the friction ring 12, 22, i.e. such that via the shift teeth 51 the sliding sleeve is prevented from sliding across until synchronous running is achieved. Rotary vibrations arising during the synchronization process are cushioned and absorbed and do not therefore lead to hard shocks which could cause premature unlocking.

In the case of synchronous running, the friction moment breaks down, the peripheral force decreases to zero and the spring mechanism 6, 6A, 7 causes a slight rotation of the stop cam 1 5, 25 in the direction of the centre of the recess 41,410. The static friction resulting from the synchronous running conditions is therefore more easily overcome, so that the unlocking behaviour is improved.

Synchronizer devices of this type are not restricted to the embodiments illustrated, as it is also possible, for example, to use discs instead of the conical friction surfaces. In addition it is also possible, for example, for the friction surfaces and the shift teeth to be directly arranged on the gear wheel and not on the clutch body.

Claims

1. Synchronizer device for positively connected shift clutches of change-speed gears, comprising an axially displaceable shift sleeve which is engageable in a clutch gear ring, a sleeve carrier disposed in a rotationally and axially fixed manner on a gear portion and supporting the shift sleeve and a friction ring formed as an engagement lock which, with rotary clearance, is in rotational connection with the sleeve carrier via rotary stops, in which springs are arranged between the sleeve carrier, in a recess in the latter, and a stop cam of the friction ring which projects into the said recess, characterised in that the rotary stops are disposed in the sleeve carrier and are formed by springs or spring mechanisms.

2. Synchronizer device as claimed in claim 1, characterised in that the spring mechanisms have a small spring path so that the rotary stops only slightly diverge from the rotary angle required for locking at different loads.

3. Synchronizer device as claimed in either one of the preceding claims, characterised in that the spring mechanisms have a high absorption.

4. Synchronizer device as claimed in any one of the preceding claims, characterised in that the spring mechanism comprises at least one cup spring.

5. Synchronizer device as claimed in claim 4, characterised in that cup springs are disposed in a recess of the sleeve carrier on both sides of the stop cam of the friction ring, and are guided via thrust plungers to be movable in the longitudinal direction in their apertures, the plungers being guided in bores in the sleeve carrier which extend perpendicular to the recess.

6. Synchronizer device as claimed in any one of claims 1 to 3, characterised in that the spring mechanisms comprise rubber or plastic springs.

7. Synchronizer device as claimed in claim 6, characterised in that the rubber springs, disposed in a recess of the sleeve carrier on both sides of the stop cam of the friction ring, comprise a metal leg extending in the direction of the stop cam.

8. Synchronizer device as claimed in claim 7, characterised in that a U-shaped spring element is disposed in the recess of the sleeve carrier, which element consists of a U-profile spring mounted by its legs, in that both legs comprise rubber or plastic springs which are externally vulcanised or attached thereto and in that the length of the spring element approximately corresponds to the width of the sleeve carrier.

9. Synchronizer device for shift clutches in change-speed gears, substantially as hereinbefore described with reference to the accompanying drawings.