GB2070159A

GB2070159A - Shift Blocker Arrangements for the Reverse Ratio of a Motor Vehicle Change-Speed Gear

Info

Publication number: GB2070159A
Application number: GB8103001A
Authority: GB
Original assignee: Adam Opel GmbH
Current assignee: Adam Opel GmbH
Priority date: 1980-02-15
Filing date: 1981-01-29
Publication date: 1981-09-03
Also published as: GB2070159B; FR2476346B3; FR2476346A1

Abstract

A shift blocker arrangement for the reverse ratio of a motor vehicle change-speed gear includes a gearshift lever 21 with a universal- joint mounting provided by a cross member 43 having a pair of mutually perpendicular joint axes 50 and 41, 42 lying in a single plane, these axes being effective respectively for the selection movement and the engagement movement of the gearshift lever. For blocking the engagement of the reverse ratio to prevent an inadvertent shift into reverse, an abutment member 60 on the cross member is engageable by a manually operable stop member constituted by a blocker pin 63 carried by the gearshift lever. <IMAGE>

Description

SPECIFICATION Shift Blocker Arrangements for the Reverse Ratio of a Motor Vehicle Change-Speed Gear This invention relates to shift blocker arrangements for the reverse ratio of a motor vehicle change-speed gear.

By the present invention there is provided a shift block arrangement for the reverse ratio of a motor vehicle change-speed gear, in which a gearshift lever has a universaijoint mounting provided by a cross member having a pair of mutually perpendicular joint axes lying in a single plane with one joint axis being effective for pivotal movement to select a gear-speed group and the other joint axis being effective for pivotal movement to engage the gear ratios in the particular gear-speed group selected, and in which the cross member is provided with an abutment member which, for blocking the engagement of the reverse ratio, is engageable by a manually operable stop member arranged on the gearshift lever.

Thereby, with a gearshift lever mounted by means of a universal joint, it is possible, ky the use of simple means, to achieve a virtually faultless blocking action preventing unintentional engagement of the reverse ratio.

Further, in a potentially simple manner, the invention allows the provision of an effective blocking action for the reverse ratio which at the same time avoids any undesirable friction between parts of the gearshift system during the ratio change.

The use of a, blocker member in conjunction with an abutment member in conformity with the invention makes it possible to achieve the requirement, in a single-shaft gearshift mechanism, of preventing rotary movement of the selector shaft beyond a certain angle.

In a development of the basic concept, it is proposed that the blocker member and the abutment member should be allowed to cooperate with each other in the selection plane for the gear ratio groups, in such a way that the selection plane remains free with regard to the gear-speed groups for the forward ratios, with the blocker member and the abutment member coming into contact with each other only just before the gear-speed plane for the reverse ratio is reached.

The blocker member and the abutment member may at the same time serve to determine the shift plane for one of the two forward-speed groups, preferably the plane for the forward ratios 1 and 2. Advantageously this at the same time provides a clear and definite delimitation of the gear-speed plane, so making it easier for the operator to find the particular plane he wants (e.g.

the shift plane for forward ratios 1 and 2), and thereby considerably facilitating the gear change.

In a preferred arrangement in accordance with the invention, the abutment member is made ramp-shaped and forms a common component with the cross member, whilst appropriately a blocker pin passing through the shift lever in a transverse direction serves as the stop member and, directed in a guide slot, is selectively movable in the longitudinal direction of the shift lever. Thereby it is possible to achieve a blocker arrangement that is effective but simple, troublefree and yet inexpensive.

Figure 1 is a fragmentary vertical longitudinal section of the front part of a single-shaft gearshift mechanism embodying a shift blocker arrangement in accordance with the present invention; Figure 2 essentially corresponds to a fragmentary section on the line Il-I I of Figure 1, in the direction of the arrows, but illustrates a slightly modified embodiment; Figure 3 is an enlarged fragmentary section of the Figure 1 embodiment approximately corresponding to the parts shown in Figure 2, with some parts in elevation; and Figure 4 is a cross-section on the line IV-IV of Figure 3.

In the drawings, Figure 1 shows the front part of a single-shaft gearshift mechanism for a motor vehicle. Details of the actual gearing, including the individual toothed pinions, have been omitted, since the present invention is not concerned with these. In Figures 1 and 2, reference numeral 10 designates the front part of the gear casing. At the bottom part of the gear casing 10 there will be seen a gearbox mainshaft (output shaft) designated as 11. At its end protruding from the gear casing 10, the mainshaft is provided with spline teeth 12 to provide a drive connection to the propeller shaft (not shown) of the vehicle. At 13, in the upper part of the gear casing 10, a single selector shaft 14 of the gearshift mechanism is mounted for rotary movement and displacement in the direction of the arrow 1 5.

Mounted at the front end of the selector shaft 14 by means of a pin 16, there is a crank arm 17 which carries a pivot pin 1 8 at its upper end. As will be seen from Figures 2 and 3, the pivot pin 18 of the selector shaft engages between the two legs 19 and 20 of the forked lower end of a gearshift lever 21.

The gearshift lever 21 consists of several parts, in a manner known per se; it includes hollow central and upper portions, and carries a shift knob 22 at its upper end. Beneath this shift knob 22 there is a pull ring 23 which, as will be explained later, controls a blocker arrangement for the reverse ratio. The pull ring 23 is arranged to be slidable along a gearshift lever part 24, and includes a guide pin 25 engaged in a guide slot in the shift lever part 24. The guide pin 25 also serves for the attachment of a pull cable 26 which is fixed to the pull ring 23 by means of a clamping screw 27.The upper surface of the pull ring 23 is in contact with a slidable nipple 28 which is loaded by a compression spring 29 at its upper end, whereby upward displacement of the pull ring 23, in the direction of the arrow 30, is possible only in opposition to the bias of the compression spring 29.

As Figure 2 shows, the central region of the gear lever is enclosed by a bellows-like rubber sleeve 11. A second rubber sleeve 32 surrounds the gear lever mounting, which has the general reference numeral 33 and will be explained in detail. The two rubber sleeves 31 and 32 are held above a propeller shaft tunnel 34 by means of a tunnel cover 35.

As is also shown in Figure 2, but especially in Figure 1 , the gear lever mounting is surrounded by a housing designated as a "gearshift dome" which is secured to the upper wall 38 of the gear casing 10 above an aperture 37 in the gear casing for the passage of the gearshift lever 21. The securing is by screws, one of which can be seen in Figure 1 and is designated 39.

Seated in the upper part of the gearshift dome 36, in the embodiment shown in Figure 2, there is a sleeve 40 in whose substantially cylindrical bore 44 (see Figures 2 and 4) there is a cross member 43 mounted by means of support pins 41 and 42, and pivotable about the common axis of these pins 41 and 42, so permitting pivotal movement of the gearshift lever 21 in the direction of the arrow 45 shown in Figure 1. In this particular embodiment the shift direction indicated by the arrow 45 lies in the longitudinal direction of the vehicle, and therefore pivotal movement in the direction of the arrow 45 is the shift movement for engaging one or other gear in a selected "gate" of the gearshift pattern. The selector shaft 14 is thereby constrained to execute a corresponding displacement in the direction of the arrow 15.

As is shown in Fioure 1 ,the cross member 43 has obilque faces 46 and 47 converging laterally upwardly and downwardly respectively, and thus making possible the pivotal movement of the shift lever 21 in the direction of the arrow 45 within the sleeve 40 or 40a (Figure 1). The oblique faces 46,47 also act as stops for limiting the pivotal movement of the shift lever 21 in the direction of the arrot 45. However, in a plane turned through 900, as Figure 2 shows, the cross member 43 lies flush against the bore 44 of the sleeve 40 or 40a.

The cross member 43 also has a central aperture which is of substantially cylindrical cross-section and is designated by reference numeral 48. The aperture 48 is traversed by the shift lever 21 ,which is enclosed by a sleeve portion 40 in this region. The shift lever 21 including the sleeve portion 49 is pivotally mounted in the cross member 43 by means of through bearing pin 50. From Figures 2 and 3 it will be apparent that the centre axes of the support pins 41 and 42 and of the throuoh bearing pin 50 intersect at a point M in the middle of the shift lever mounting, such that a universal joint action is provided. The bearing pin 50 permits pivotal movement of the shift lever 21 in a direction, shown by arrow 51, which is at right angles to the pivotal direction 45.In order to limit the pivotal movement in the direction of the arrowt, the cross member 43 has obtique faces 52 and 53, shown in Figures 2 and 3. The oblique faces 52 diverge upwardly and the oblique faces 53 diverge downwardly. From Figures 2 and 3 it will be appreciated that pivotal movement of the shift lever 21 in the direction of the arrow 51 produces a rotary movement of the selector shaft 14. This pivotal movement of the shift lever 21 in the direction of the arrow 51 therefore serves for the selection of the particular gear-speed group desired (forward ratios 1 and 2, or 3 and 4, or the reverse ratio).

In the position shown in Figures 2 and 3, the shift leve 21 i he plane for the two forward ratios 1 and 2. In Figure 2 the shift plane for the forward ratios 3 and 4 is indicate by a dotdash line 54, and the shift plane for the reverse ratio is designated by a dot-dash line 55. In order to move the shift lever 21 from the plane for the forward ratios 1 and 2 into the plane 54 for the forward ratios 3 and 4, pivotal movement in the direction of the arrow 56 is necessary. In the embodiment shown in Figure 2, inside the rubber bellows 32 the shift lever 21 is engaged by a pull shackle 57 the bottom end of which tightly surrounds a profiled retaining pin 58 secured to the shift dome 36. The shackle 57 is thereby pretensioned so as to bias the shift lever 21 into the shift plane 54 for the forwar ratios 3 and 4.In order to move the shift lever 21 into the shift plane shown in Figure 2, namely for forward ratios 1 and 2, it is therefore necessary to overcome the resistance of the shackle 57, and the same is true when the shift tever 21 is to be moved in the direction of the arrow 59 into the shift plane 55 for the reverse ratio.

Figures 2 and 3 will be seen to include a configuration such that pivotal movement of the shift lever 21 in the direction of the arrow 59, and thus into the plane 55 for the reverse ratio, from the position indicated in Figures 2 and 3 is not readily possible. Specificallh , at both sides of the shift lever 21 and its sleeve portion 49, the cross member 43 has an upwardly extending rampshahd formation (shown in dash lines and designated as 60 in Figures 2 and 3). This rampshaped formation 60 has an abutment face 61 rising vertically upwardly, and a sliding face 62 falling away downwardly in a rounded-off shape at the other s de. This ramp-shaped formation 60 serves as a fixed abutment for a blocker pin 63 which is secured to a sliding member 64 that is displaceable in a vertical direction inside the sleeve portion 49.

*In the position of the gearshift lever 21 shown in Figures 2 and 3, the blocker pin 63 serving as a reverse ratio blocker is in abutment with the vertical face 61 of the ramp-shaped formation 60.

As will be seen particularly from Figures 1 and 3, the blocker pin is guided in the axial direction of the gearshift lever 21 in a guide slot 65 of the sleeve portion 49. As is shown in Figure 2, the sliding member 64 is secured to the lower end of the pull cable 26. The sliding member 64 and therefore also the blocker pin 63 are springloaded by a compression spring 66 which resiliently holds the blocker pin 63 in the blocking position indicated in Figs.1,2 and 3. In the position of the blocker arrangement 60 and 63 which is shown in Figures 2 and 3, it is accordingly not possible to pivot the gearshift lever 21 in the direction of the arrow 59 into the shift plane 55 provided for the reverse gear ratio.

In order to overcome the blocking action of the reverse ratio blocker, it is necessary to move the pull ring 23 upwardly in the direction of the arrow 30 until the blocker pin 63 is above the rampshaped formation 60. Thereupon, the gearshift lever 21 can be moved in the direction of the arrow 59, and the blocker pin 63 can slide along the curved sliding face 62 of the ramh-shaped fixed abutment 60.

It will be evident from Figures 2 and 3 and the above description that the reverse-ratio blocker rrangement, essentially consisting of the blocker pin 63 and the ramp-shaped fixed abutment 60, is also effective to determine the shift plane for the two forward ratios 1 and 2.

From the above description and from the drawings it will be evident that the embodiment shown in Figures 1, 3 and 4 is very similar to the embodiment shown in Figure 2. However, in the Figure 2 embodiment the sleeve 40 has a lesser height than the sleeve 40a of Figures 1,3 and 4 supported at the base of the sh ft dome 36a.

Moreover, Figure 3 shows the sleeve 40a to be fixed in the shift dome 36a by a clip 67, and for axial fixing the clip 67 engages in two lateral grooves 68 and 69 of the sleeve 40a, with a lug 71 being engaged in an aperture 72 to prevent twisting movement.

As is shown in Figures 3 and 4, to prevent friction and wear two steel discs 70 are provided between the cross member 43 and the sleeve 40a. These steel discs are mounted on the support pins 41 and 42.

As materials for the cross member 43 and the sleeve 40a (or 40), it is possible to use plastics material (for example polyamide reinforced by glass fibre).

Claims

1. A shift blocker arrangement for the reverse ratio of a motor vehicle change-speed gear, in which a gear-shift lever has a universal-joint mounting provided by a cros member having a pair of mutually perpendicular joint axes lying in a single plane with one joint axis being effective for pivotal movement to. select a gear-speed group and the other joint axis being effective for pivotal movement to engage the gear ratios in the particular gear-speed group selected, and in which the cross member is provided with an abutment member which, for blocking the engagement of the reverse ratio, is engageable by a manually operable stop member arranged on the gearshift lever.

2. A shift blocker arrangement according to claim 1, in which the stop member and abutment member co-operate in the selection plane for the gear-speed groups in such a way that the selection plane for the gear-speed groups for the forward ratios remains free, and the stop member and abutment member come into contact only immediately prior to the shift plane for the rv se ratio being reached.

3. A shift blocker arrangement according to claim 1 or 2, in which the stop member and abutment member also serve to determine the shift plane for one of the two forward gear-speed g oups.

4. A shift blocker arrangement according to any one of claims 1 to 3, in which the abutment member comprises a ramp-shaped portion of the cross member.

5. A shift blocker arrangement according to any one of claims 1 to 4, in which the stop member comprises a blocker pin that passes through the gear shift lever in a transverse direction and is arranged, in conjunction with a guide slot, for selective movement longitudinally of the gearshift lever.

6. A shift blocker arrangement according to claim 5, in which the blocker pin is biased towards a lower, blocking position by spring loading, and is manually movable, by means of a pull member overcoming the spring loading, into an upper, free position with the ends of the guide slot acting as stops establishing the lower and upper extreme positions of the blocker pin.

7. A shift blocker arrangement according to any one of claims 1 to 6, in which the gearshift lever extends through a central aperture in the cross member and the gearshift lever is mounted in the cross member by means of a through pivot pin.

8. A shift blocker arrangement according to claim 7, in which the aperture in the cross member is provided with oblique faces which, proceeding from the middle of the joint, diverge conically longitudinally of the gearshift lever.

9. A shift blocker arrangement according to claim 8, in which the oblique faces serve as stops for limiting the gearshift lever movement within the selection plane.

10. A shift blocker arrangement according to any one of claims 1 to 9, in which the abutment member is ramp-shaped and is disposed laterally of the gearshift lever and extends on both sides of the gearshift lever and parallel thereto.

11. A shift blocker arrangement according to any one of claims 1 to 10, in which the abutment member has an abutment face for the blocker member extending longitudinally of the gearshift lever, and at its upper end the abutment face makes a transition at an acute angle into a sliding face curved convexly in a downward direction.

12. A shift blocker arrangement according to any one of claims 1 to 11, in which the cross.

member is mounted in a cylindricat oint sleeve by means of two diametrically opposed pivot pins.

13. A shift blocker arrangement according to claim 12, in which the joint sleeve is arranged in a shift dome secured to a gear casing and is fixed with respect to the latter in an axial direction by means of a clip and in a rotary direction by means of a lug which engages a recess in the shift dome.

14. A shift blocker arrangement according to any one of claims 1 to 13, in which the cross member is provided with external oblique faces comprising upwardly converging upper oblique faces and downwardly converging lower oblique faces, and the oblique faces serve as stops for limiting the movement of the gear-shift lever within the particular shift plane.

15. A shift blocker arrangement according to any one of claims 1 to 14, in which the gearshift lever is connected to operate a single-shaft gear selector mechanism.

1 6. A shift blocker arrangement for the reverse ratio of a motor vehicle change-speed gear, substantially as hereinbefore particularly described and as shown in Figures 1,3 and 4 of the accompanying drawings.

17. A shift blocker arrangement for the reverse ratio of a motor vehicle change-speed gear, substantially as hereinbefore particularly described and a shown in Figure 2 of the accompanying drawings.