GB2127503A

GB2127503A - Selector mechanism having a manual gearshift lever for main and auxiliary gearboxes in series

Info

Publication number: GB2127503A
Application number: GB08325963A
Authority: GB
Inventors: Rudolf Voshage
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1982-09-29
Filing date: 1983-09-28
Publication date: 1984-04-11
Also published as: FR2533718A1; GB8325963D0; DE3235976C2; AT379875B; GB2127503B; DE3235976A1; FR2533718B1; ATA344383A

Abstract

In a selector mechanism having a double H-shaped gearshift pattern for multispeed gearboxes of motor vehicles, a selector shaft 7 which connects a manual gearshift lever to a multispeed main gearbox causes, upon changing between H-shaped gearshift patterns, a selector servomotor 16 to change the gear of a two-speed auxiliary gearbox. A lock 17 blocks the manual gearshift shaft to prevent a gear being selected in the main gearbox until shifting is completed in the auxiliary gearbox. The lock 17 comprises two locking cams 20 rigidly mounted on the selector shaft and locking bolts 22, 23 which are movable at right angles to the selector shaft 7. A position- dependent locking gate 37 of the auxiliary gearbox 13 operates on those ends 26 of the locking bolts 22, 23 opposite to the locking cams. <IMAGE>

Description

SPECIFICATION Selector mechanism for a multispeed gearbox having a manual gearshift lever The invention relates to a selector mechanism for a multispeed main gearbox in series with a two speed auxiliary gearbox, in which mechanism a main selector shaft, operatively connected to a manual gearshift lever operable in accordance with a double H-shaped gearshift pattern, is engageable with a selector means of the multispeed main gearbox, and, when changing from one H-shaped gearshift pattern to the other, actuates a control device for a selector servomotor to change the gears of the auxiliary gearbox, the mechanism including a lock for blocking the manual gearshift lever.

In a known selector mechanism of this type (German Offenlegungsschrift OS 28 13 099) the lock as such is constantly operative, typically by the provision of an auxiliary locking force, in order to prevent an inadvertent changeover of the manual gearshift lever from one H-shaped gearshift pattern to the other. If the driver wishes to change from the H-shaped gearshift pattern in use to the other, the lock must first be released manually.

In a different type of known selector mechanism (Swiss Patent Specification 247 583) for a multispeed gearbox in which the main and auxiliary gearboxes are controlled manually without the use of selector servomotors, locking bolts which are axially movable along a solid shaft fixed to the gearbox each cooperate at their two bolt ends with a respective locking gate, one of which is connected to the sliding selector sleeve of the two-speed auxiliary gearbox and the other of which is connected to one of the sliding selector sleeves of the main gearbox. The locking cams on the locking gates can, inter alia, also be associated with one another in such a manner that the gearshift of the higher gears is blocked at one speed ratio of the auxiliary gearbox and the gearshift of the lower gears of the main gearbox is blocked at the other speed ratio.

The present invention seeks to provide a selector mechanism which enables the manual gearshift lever to be changed, at any time and without difficulty, to the other H-shaped gearshift pattern in each case-but to prevent, in this connection, one of the gears of this other Hshaped gearshift pattern from being able to be engaged if the auxiliary gearbox is not yet at its new speed ratio.

According to the present invention there is provided a selector mechanism for a multispeed main gearbox in series with a two speed auxiliary gearbox, in which mechanism a main selector shaft, operatively connected to a manual gearshift lever operable in accordance with a double Hshaped gearshift pattern, is engageable with a selector means of the multispeed main gearbox and, when changing from one H-shaped gearshift pattern to the other, actuates a control device for a selector servomotor to change the gears of the auxiliary gearbox, the mechanism comprising a releasable lock for preventing the manual gearshift lever engaging a gear associated with the H-shaped gearshift patterns when changing the speed ratio of the auxiliary gearbox, the lock having two locking cams, which are fast on the selector shaft, and are associated with respective locking bolts mounted for axial displacement at right angles to the selector shaft each of bolts which can be moved out of a locking position-in which one of the bolt end lies in the path of movement of a locking cam-by resilient means into a release position in which the bolt end in question lies outside said path of movement, the bolt end of each of the lock bolts opposite to the associated locking cam, is retained by a locking surface of a locking gate which is connected, depending on position, to a selector means of the auxiliary gearbox and which has for each speed position of the auxiliary gearbox a seat or detent for the release position of the respective locking bolt which, instead of the locking surface, only moves into the area of the bolt end if the auxiliary gearbox is at its new speed ratio, and wherein the main selector shaft performs rotary movement for gear selection and axial movement for engagement of gears and includes two cam-actuated levers having a mutual angular offset and each having a locking slot for the axial retention thereof by said locking bolts.

Preferably the locking gate is arranged on a sliding auxiliary selector shaft to connect an axial piston of the selector servomotor to the selector means of the auxiliary gearbox.

The main selector shaft has a selector lever which is rigidly connected thereto and which cooperates with two selector fingers arranged for movement at right angles to said main selector shaft. In this case, cam-actuated levers and said selector lever are integral with a common hub.

Preferably, the arc or curve length, measured in the circumferential direction of the main selector shaft, of each locking slot is substantially equal to half the angular interval between the positions of the main selector shaft for the two outer gear positions ((1)-(2) and (7)-(8)) of the double Hshaped gearshift.

A preferred embodiment of the invention will now be described by way of example, with reference to the accompanying drawings in which: Fig. 1 shows a diagrammatic view of a known selector mechanism, Fig. 2 shows a selector mechanism according to the invention in a partial section along the line Il-I I in Fig. 3, the partial section being confined to those parts of the mechanism which are most essential for describing the invention, Fig. 3 shows a partial section through the selector mechanism according to the invention, along the line Ill-Ill in Fig. 2, and Fig. 4 shows a partial section through the selector mechanism according to the invention, along the line IV-lV in Fig. 2.

With reference to Fig. 1, two sliding selector sleeves 46 and 47 for selecting four gear ratios of a main gearbox 14 are connected kinematically to selector forks, 48, 49, respectively, the associated parts of a selector mechanism 1 2 not being shown in detail. The two selector forks 48 and 49 are actuated by a first selector finger 10 of a selector shaft 7, which is connected kinematically to a manual gearshift lever 6, if the gearshift lever 6 is in the H-shaped gearshift pattern 8 of the lower gears (1) to (4). The selector forks 48 and 49 are actuated by a second selector finger 11 on the selector shaft 7 if the manual gearshift lever 6 is in the H-shaped gearshift pattern 9 of the higher gears (5) to (8).The manual gearshift lever 6 is mounted by means of a bearing arrangement 52 in such a manner that its upper end, which is in the form of a handle 53, is pivotably guided or arranged both in a selection plane 51-51 and in the gear positions (1 )-(2); (3)-(4); (5)-(6) and (7)-(8) which lie perpendicular to the latter and are arranged in two H-shaped gearshift patterns.

An auxiliary gearbox 13 in the form of a single plane planetary gear train is arranged for operation in series with the main gearbox 14, it being possible for the auxiliary gearbox to be switched by a selector servomotor 1 6 of a selector mechanism 36 between a transmission step 1 8 having a speed ratio between the input and output speeds of more than 1 and a transmission step 1 9 having a speed ratio equal to 1. The selector servomotor 16 is controlled by a control valve 1 5 actuated by a control gate 54 of the selector shaft 7 if the manual gearshift lever 6 changes from one H-shaped gearshift pattern 8 or 9 to the other.In this case the selector finger 10 is associated with the transmission step 18 and the selector finger 11 is associated with the transmission step 1 9 so that the lower gears (1) to (4) in the H-shaped gearshift pattern are formed by multiplication of the four transmission steps of the main gearbox 14 by the speed ratio of the auxiliary gearbox 13 which is greater than 1, whilst the higher gears (5) to (8) of the H-shaped gearshift pattern 9 are each equal to the speed ratios of the main gearbox 14.

The selector mechanism according to the invention corresponding to Figs. 2 to 4 is identical to the selector mechanism according to the prior art corresponding to Fig. 1 in the previously described features so that the corresponding reference numerals are used for Figs. 2 to 4, but the description has not been repeated.

Moreover, both the known selector mechanism and the selector mechanism according to the invention have a lock 1 7 cooperating with the selector shaft 7, and in the case of the lock of the selector mechanism according to the invention the following features or designs of the known lock 1 7 in Fig. 1 are still used-but for a different purpose and with a modified mode of operation: With reference to Fig. 1, the selector shaft 7 has two locking cams 20 and 21 which are associated with H-shaped gearshift patterns 8 and 9, respectively, and which are rigidly connected to or formed on the shaft.The cams cooperate with a facing bolt end 25 of at least one locking bolt 22 which is arranged at right angles to the selector shaft 7 and is mounted for axial movement between a locking position 24 and a release position 29. The locking bolt 22 is biassed into the release position 29 by resilient means 28. When in the locking position 24, the bolt end 25 lies within the path of movement, whereas when in the release position 29, it lies outside the path of movement of the locking cams 20 or 21.

The other object and the other purpose of the known lock 1 7 of Fig. 1 are to prevent reliably both an inadvertent changeover of the manual gearshift lever 6 between the H-shaped gearshift patterns 8, 9 and the change of gear in the auxiliary gearbox 13 which is triggered in this case by the control gate. Therefore the known lock 1 7 as such is active continuously and in such a manner that the manual gearshift lever 6 is arranged so as to be freely movable in the Hshaped gearshift pattern of each selected speed ratio 1 8 or 19, but is prevented from moving out the gearshift pattern in question. The known lock 1 7 must first be released by hand if the driver wishes to change over to the other H-gearshift pattern.

In contrast, with the selector mechanism according to the invention the lock 1 7 is intended to enable a change, at any time and without difficulty, between the H-gearshift patterns 8, 9 together with the associated change of gear in the auxiliary gearbox 1 3 by the selector servomotor 16, but to block automatically the engagement of the gears of the H-shaped gearshift pattern 8 or 9 associated with the new speed ratio 1 8 or 1 9 if the auxiliary gearbox 1 3 is not yet at the new speed ratio.

In principle, this problem is solved by the selector mechanism shown in Figure 2 in that the lock 1 7 is inactive during the movements of the manual gearshift lever 6 (cp. The diagrammatic view in Fig. 1) in the selection plane 51-51 and only the deflection of the gearshift lever 6 in the directions of the respective gears (1)(2) etc. can be blocked. Each locking cam 20 or 21 is associated with a locking bolt 22 or 23 respectively and the bolt ends 26 which are opposite to the locking cams 20 or 21 cooperate with a position-dependent locking gate 37 of the selector mechanism 36 of the auxiliary gearbox 13.

In the embodiment in Figs. 2 to 4 this occurs as follows: The selector shaft 7 of the selector mechanism 12 is both arranged near to a sliding selector shaft 39 of the selector mechanism 36 and connected kinematically to the manual gearshift lever 6 (Fig.

1)-in a manner no longer shown-so that a selector lever 45 (shown in Figure 3), which is non-rotatably connected thereto, performs angular movements 33, 34 in a selection plane 55-55 perpendicular to the axis 56-56 of the selector shaft 7 to select one of the gear positions, i.e. for movement of the lever 6 across the 'gate' of the H pattern and performs translational movements 30 or 31 in the directions of the axis 56-56 to engage a selected one of the gears (1) to (8).The sliding selector shaft 39 connected the axial piston 40 of the selector servomotor 1 6 to a control lever 57 which, in a manner not shown, actuates a sliding selector sleeve to change the gear of the auxiliary gearbox 13 and, as shown in Fig. 2, occupies the illustrated position when in the transmission step 18, by the position indicated by dot-dash lines when in the transmission step 1 9.

The locking cams 20, 21 are in the form of cam-actuated levers 42 and 43, each of which has at the lever and a locking slot 44 extending in the circumferential direction to the axis 56-56 and which combine with a hub 50 and the selector lever 45 to form one part. The hub 50 is arranged concentrically and connected rigidly to the selector shaft 7 by a cotter pin 58, the camactuated levers 42 and 43 having a mutual rotary angle offset 41.

The locking slot 44 of the cam-actuated lever 42 lies concentrically to a plane 59-59 which includes the axis of the associated locking bolt 22 and lies perpendicular to the axis 56-56 of the selector shaft 7. The corresponding arrangement is provided for the locking slot 44 of the other cam-actuated lever 43 in the plane IV--IV which includes the axis of the associated locking bolt 23. When in the locking position 24, the bolt ends 25 lie within the annular space 62, but when in the release position 29, they lie outside the annular space 62 which is circumscribed by the cross-section of the associated locking slot 44 in an imaginary rotary movement about the axis 56-56 of the selector shaft 7.Thus, both the locking cams 20 and 21 have a free movement of 3600 in the circumferential directions of the axis 56-56 of the selector shaft 7 relative to their associated locking bolts 22 and 23, respectively.

If the selector lever 45 is in its selection plane 55-55; that is, the selector lever 45 can pass without difficulty through an angle of rotation 32 which is formed by the gear positions (1 )-(2) and (7) and (8). If, when changing the H gearshift pattern, the selector lever 45 moves into the intermediate rotary angle area 63 in the selection plane 55-55, an actuation-which is no longer shown in the drawings--of the control valve 1 5 (Fig. 1) is effected to change the gear of the auxiliary gearbox 13.

The locking gate 37 has a seat or receiver 38, in the form of a recess on the circumference of the sliding selector shaft 39, for the release position 29 of the locking bolts 22 and 23. In the transmission step 18, the seat 38 lies concentrically to the plane 59-59 of the locking cam 20 and locking bolt 22, whereas in the transmission step 19 it lies concentrically to the plane IV-lV of the locking cam 21 and locking bolt 23. Those sections of the cylindrical outer wall 35 of the sliding selector shaft 39 which lie axially on both sides of the seat 38 serve as locking faces 35a and 35b of the locking gate 37 to actuate the locking bolts 22, 23 to move into their respective locking positions 24.

When in the illustrated position, the selector lever 45 is situated in its selection plane 55-55 in the rotary angle position of the gear (3)-(4), that is in the H gearshift pattern 8 of the lower gear (1) to (4). In this position the locking slot 44 of the cam-actuated lever 42 lies within the area of contact or engagement with the lower bolt end 25 of the associated locking bolt 22. Since the axes of the locking bolts 22 and 23 lie within a plane II which includes the axis 56-56 of the selector shaft 7, the locking slot 44 of the locking bolt 23 lies outside the area of engagement with the lower bolt end 25 of the associated locking bolt 23 because of the angular offset 41.In the H gearshift pattern 8 of the lower gears the auxiliary gearbox 13 must be at its speed ratio 18-and the associated control lever 57 and the sliding selector shaft 39 must therefore be in the positions as shown in the drawing.

In the event that, following the actuation of the control valve 1 5 to switch over to the speed ratio 18-for example, because the transmission is cold or the pressure for the selector servomotor 1 6 is too low-the selector lever 45 is already in the angular area or range 33 of the two lower gear positions (1 )-(2) and (3)-(4), but that the sliding selector shaft 39 has moved out of its previous position for the speed ratio 1 9 only into an intermediate position 67, the upper bolt end 26 of the locking bolt 22 is in engagement with the locking face 35a so that the lower bolt end 25 engages in the locking slot 44 of the camactuated lever 42.Thus, the bolt end 25 is located in that path of movement 27-27 of the side walls 60 and 61 of the locking slot 44 which is parallel to the axis 56-56. Consequently, the side wall 61 of the slot blocks the selection path 30 of the selector shaft 7 for engaging the gears (1) and (3) and the side wall 60 of the slot blocks the selection path 31 for engaging the gears (2) and (4) since the arc length 64 of each locking slot 44 is approximately equal to half the angular interval 32 between the positions 65 and 66 of the selector lever 45 for the two outer gear positions (1 )-(2) and (7)-(8) of the double H gearshift pattern 5 so that, when the selector lever 45 is pivoted out of the position for the gear (3)-(4) into the position 65 for the gear (1 )-(2), the side walls 60 and 61 of the slot continue to remain engaged with the bolt end 25 until the changeover in the auxiliary gearbox 13 takes place and the locking bolt 22 has been displaced by the associated helical spring 28 together with its upper bolt end 26 into the seat 38 which is not available in place of the locking face 35a.

If the changeover of the auxiliary gearbox 13 to the other speed ratio 19 is, for the reasons mentioned, delayed in relation to the changeover of the selector lever 45 to the associated new angle of rotation 34, then the upper end 26 of the locking bolt 23 is also engaged with the locking face 35b. When the selector lever 45 is changed over-that is in the angle of rotation 63-the locking slot 44 of the cam-actuated lever 42 moves out of the area of engagement with the locking bolt 22 whilst the locking slot 44 of the cam-actuated lever 43 at the same time moves into engagement with the lower bolt end 25 of the locking bolt 23 because the rotary angle offset 41 is approximately equal to half the angular interval 32 between the positions 65 and 66 of the selector lever 45. Consequently, the locking slot 61 blocks the selection path 30 of the selector shaft 7 for engaging the gears (5) and (7) whilst the side wall 60 of the slot blocks the selection path 31 for engaging the gears (6) and (8). After the changeover of the auxiliary gearbox 13 has taken place, the seat 38 is available in place of the locking face 35b to initiate the displacement of the locking bolt 23 into the release position 29 by the associated helical spring 38.

Claims

1. A selector mechanism for a multispeed main gearbox in series with a two speed auxiliary gearbox, in which mechanism a main selector shaft, operatively connected to a manual gearshift lever operable in accordance with a double Hshaped gearshift pattern, is engageable with a selector means of the multispeed, main gearbox, and, when changing from one H-shaped gearshift pattern to another, actuates a control device for a selector servomotor to change the gears of the auxiliary gearbox, the mechanism comprising a releasable lock for preventing the manual gearshift lever engaging a gear associated with the H-shaped gearshift patterns when changing the speed ratio of the auxiliary gearbox, the lock having two locking cams, which are fast on the selector shaft, and are associated with respective locking bolts mounted for axial displacement at right angles to the selector shaft each of bolts which can be moved out of a locking positions which one of the bolt ends lies in the path of movement of a locking cam-by resilient means into a release position in which the bolt end in question lies outside said path of movement, the bolt end of each of the lock bolts opposite to the associated locking cam, is retained by a locking surface of a locking gate which is connected, depending on position, to a selector means of the auxiliary gearbox and which has for each speed position of the auxiliary gearbox a seat or detent for the release position of the respective locking bolt which, instead of the locking surface, only moves into the area of the bolt end if the auxiliary gearbox is at its new speed ratio, and wherein the main selector shaft performs rotary movement for gear selection and axial movements for engagement of gears and includes two camactuated levers having a mutual angular offset and each having a locking slot for the axial retention thereof by said locking bolt.

2. A selector mechanism according to claim 1, the locking gate is arranged on a sliding auxiliary selector shaft to connect an axial piston of the selector servomotor to the selector means of the auxiliary gearbox.

3. A selector mechanism according to claim 1 or 2, the main selector shaft has a selector lever which is rigidly connected thereto and which cooperates with two selector fingers arranged for movement at right angles to said main selector shaft.

4. A selector mechanism according to claim 3, wherein cam-actuated levers and said selector lever are integral with a common hub.

5. A selector mechanism according to any one of claims 1 to 4, wherein the arc or curve length, measured in the circumferential direction of the main selector shaft, of each locking slot is substantially equal to half the angular interval between the positions of the main selector shaft for the two outer gear positions ((1 )to(2) and (7)-(8)) of the double H-shaped gearshift pattern.

6. A selector mechanism according to any one of claims 1 to 5, wherein the angular offset of the cam-actuated levers is substantially equal to half the angular interval between the positions of the main selector shaft for the two outer gear positions ((1)-(2) and (7)-(8)) of the double Hshaped gearshift pattern.

7. A selector mechanism for a multi-speed main gearbox in series with a two speed auxiliary gearbox, substantially as described herein with reference to and as illustrated in Figures 1 to 4 of the accompanying drawings.