Shift device for automotive automatic transmission

Abstract: A bell crank lever (33) is used to operatively interconnect a transmission control cable (27) with a shift lever (9). The bell crank lever (33) is pivoted about an axis which is located at essentially the same level as the axis about which the shift lever (9) is pivotal. Connection between the shift lever (9) and the bell crank lever (33) is achieved by means of a pin (17) which projects from one side of a shaft which forms part of a detent mechanism (11, 21) and an elongate slot formed in one end of the bell crank lever (33). The bell crank lever (33) is pivotally mounted on a plate (21) which forms part of the detent mechanism (11, 21) and in which detent recesses are formed. This facilitates the acucurate assembly of the device. Further, as the bell crank lever (33) is pivoted at substantially the same height as the pivot shaft of the shift lever (9) and arranged above the bottom wall of the base bracket (5), a lever effect equal to that of the conventional construction is achieved. Furthermore, since there is no need for an intermediate shaft, reduction in play and cost are also achieved.

Description: The present invention relates generally to a shift lever construction for an automatic transmission and more specifically to a shift lever construction which features an improved shift feeling. One example of a conventional floor-mounted shift devices for an automatic transmission is disclosed in JP-U-60-195225. This document discloses a shift device as specified in the preamble of claim 1. However, with this arrangement, the pivot point of a bellcrank lever which transmits an operating force to a control cable of the automatic transmission, is positioned below both the pivot point of a shift lever and a base bracket face. Thus, in order to increase the lever effect, it is necessary to use an intermediate link to operatively connect one end of the bellcrank with the shift lever. Due to provision of the intermediate link, an undesirable amount of play tends to occur at the connections and thus the operation feeling is deteriorated. Furthermore, due to increase in number of parts, both the weight and the production cost are increased. In view of the above-mentioned drawbacks, it is an object of the present invention to provide a shift device which reduces both undesirable play and production cost, and assures positional accuracy during the construction of the device while assuming a lever effect equal to that of a conventional device. In brief, the object is achieved by an arrangement wherein a bell crank lever is used to operatively interconnect a transmission control cable with a shift lever. The bell crank lever is pivoted about an axis which is located at essentially the same level as the axis about which the shift lever is pivotal. Connection between the shift lever and the bell crank lever is achieved by means of a pin which projects from one side of a shaft which forms part of a detent mechanism, and an elongate slot formed in one end of the bell crank lever. An additional feature of the invention comes in that the bell crank lever is pivotally mounted on a plate which forms part of the detent mechanism and in which detent recesses are formed. This facilitates the accurate assembly of the device. Further, as the bell crank lever is pivoted at substantially the same height as the pivot shaft of the shift lever and arranged above the bottom wall of the base bracket, a lever effect equal to that of the conventional construction is achieved. Furthermore, since there is no need for an intermediate shaft, reduction in play and cost are also achieved. More specifically, the present invention relates to a shift device for an automatic transmission comprising : a base bracket with a base member from which essentially vertical side wall extends, the base bracket being adapted for connection to a vehicle body ; a shift lever ; a pivot shaft mounted pivotally with respect to the side wall of the base bracket and providing a first axis, said shift lever being mounted on the pivot shaft so as to be pivotal about said axis ; a lever member mounted on the pivot shaft so as to be rotatable with the shift lever ; a position plate arranged to extend parallel with the direction in which the shift lever is pivotal, the position plate having first positioning recesses with which a position pin operatively mounted on the shift lever is detachably engageable ; and lever means for transmitting an operating force from the shift lever to a control cable of the automatic transmission, said lever means being pivotal about a second axis which is located at essentially the same level as said first axis and arranged above a bottom wall of the base bracket, characterized in that said position plate further includes second positioning recesses with which a check ball supported on a free end of the lever member is detachably engageable. The invention is also characterized in that said lever means comprises a bell crank lever pivotally supported on said position plate, said bell crank lever having one end operatively connected with the transmission control cable and another end operatively connected with said lever member. Furthermore, the operative connection between the other end of said bell crank lever and the lever member includes an elongate slot in one of said bell crank lever and said lever member ; and a pin which is rigid with the other of said bell crank lever and said lever member. In the shift device according to the invention, said shift lever and said lever member are respectively rigid with the pivot shaft being rotatably mounted to the side wall of the base bracket. It is to be pointed out there that, advantageously, said lever means is arranged to pivot about said second axis in a first rotational direction when said shift lever pivots about said first axis in a second rotational direction which is opposite to said first rotational direction. In the drawings : Figs. 1 and 2 show an embodiment of the present invention. Fig. 1 is a perspective view and Fig. 2 is a vertically sectioned view of the device of Fig. 1. Figs. 1 and 2 show an embodiment of the present invention. Designated by numeral 1 is a shift lever device for an automatic transmission. The shift lever device 1 comprises a shift lever 9 which is supported by a pivot shaft 7 on the vertical side wall 5a of a pan-shaped base bracket 5 fixed to a floor panel 3 of a vehicle body. A detent mechanism includes a lever member 11 which is pivotally movable in accordance with the pivotal movement of the shift lever 9. The lever member 11 is rigid with and extends from the pivot shaft 7. The detent mechanism further includes a position plate 21 which extends along a plane which is normal to the axis about which the shift lever rotates, i.e. parallel with the direction in which the shift lever 9 is movable. The position plate 21 has front and rear flanges 21a and 21b secured to the fore and aft vertical end wall 5a of the base bracket 5. The plate 21 is formed with notches 19 and 23. A position pin 17 which is vertically movable along an elongate slot formed in the shift lever 9 and constantly biased upward by a spring 15 is detachably engageable or receivable in the notches 19 of the position plate 21. A check ball 25 is supported on a free end 11a of the lever member 11 and is detachably engageable with check portions defined by the notches 23. A force transmission means 29 is arranged such that, upon pivotal movement of the lever member 11, force is transmitted to control cable 27 of the automatic transmission (not shown). A pivot shaft 31 of a force transmission means 29 is positioned at approximately the same height as the pivot shaft 7 of the shift lever 9 and arranged above a bottom wall 5b of the base bracket 5. Upon manipulation of a button 9b mounted to a knob 9a of the shift lever 9, the position pin 17 is moved downwardly in a manner which disengages the same from the neutral position (N), drive position (D), etc. notches or positioning recesses 19 of the position plate 21. After the shift lever 9 is moved either forward or rearward and the force applied to the button 9b is removed, the position pin 17 moves upward under the bias of spring 15 and engages the notches 19 in a newly selected position (for example, parking position (P), second position (S), etc.,). In this embodiment the transmission means 29 comprises a bellcrank lever 33 which is pivotally supported by the pivot shaft 31. This shaft 31 is supported by the position plate 21. One end portion 33a of the lever 33 is formed with an elongate slot 37 in and along which a pin 35, which projects from a side portion of the lever member 11, is slidably engaged. The other end portion 33b of the supporting plate 33 is formed with an opening 39 to which the control cable 27 is pivotally connected. A grommet 43 which supports the control cable 27, is fitted in a recess 41 formed in the vertical wall 5a of the base bracket 5. Since the pivot shaft 31 of the transmission means 29 is positioned at substantially the same height as the pivot shaft 7 of the shift lever 9, and arranged above the bottom wall 5b of the base bracket 5, a lever effect equal to that of the conventional construction is obtained. Furthermore, since the pivot shaft 31 is connected to the position plate 21, the ease and precision with which assembly can be carried out is increased. In addition to the above, the depth of the device is minimized and thus alleviating road clearance related design problems.

Claims: A shift device for an automatic transmission, comprising : a base bracket (5) with a base member from which essentially vertical side wall (5a) extends, the base bracket being adapted for connection to a vehicle body (3) ; a shift lever (9) ; a pivot shaft (7) mounted on the side wall (5a) of said base bracket (5) and providing a first axis, sais shift lever (9) being mounted on the pivot shaft (7) so as to be pivotal about said first axis ; a lever member (11) mounted on the pivot shaft (7) so as to be rotatable with the shift lever (9) ; a position plate (21) arranged to extend parallel with the direction in which the shift lever (9) is pivotal, the position plate (21) having first positioning recesses (19) with which a position pin (17) operatively mounted on said shift lever (9) is detachably engageable ; and lever means (29) for transmitting an operating force from said shift lever (9) to a control cable (27) of the automatic transmission, said lever means being pivotal about a second axis which is located at essentially the same level as the pivot shaft (7) said first axis and arranged above a bottom wall of the base bracket (5), characterized in that said position plate (21) further includes second positioning recesses (23) with which a check ball (25) supported on a free end (11a) of the lever member (11) is detachably engageable. A shift device as claimed in claim 1, wherein said lever means (29) comprises : a bell crank lever (33) pivotally supported on said position plate (21), said bell crank lever having one end (33b) operatively connected with the transmission control cable and another end (33a) operatively connected with said lever member (11). A shift device as claimed in claim 2 wherein the operative connection between the other end (33a) of said bell crank lever (33) and the lever member (11) consists of : an elongate slot (37) in one of said bell crank lever (33) and said lever member (11) ; and a pin (35) which is rigid with the other of said bell crank lever (33) and said lever member (11). A shift device as claimed in any one of claims 1 to 3, wherein said shift lever (9) and said lever member (11) are respectively rigid with the pivot shaft (7), said pivot shaft (7) being rotatably mounted to the side wall (5a) of the base bracket (5). A shift device as claimed in any one of claims 1 to 4, wherein said lever means (29) is arranged to pivot about said second axis in a first rotational direction when said shift lever (9) pivots about said first axis in a second rotational direction which is opposite to said first rotational direction.

Inventors: ISHIZUKI MASAHARU C O FUJI KIK, TOGANO NORIO C O FUJI KIKO CO, ISHIZUKI, MASAHARU, TOGANO, NORIO, ISHIZUKI, MASAHARU, C/O FUJI KIKO CO., LTD., TOGANO, NORIO, C/O FUJI KIKO CO., LTD.
Applicants: FUJI KIKO KK, NISSAN MOTOR, FUJI KIKO CO., LTD., NISSAN MOTOR CO., LTD.
Application year: 1990
Main classification: B60K20
IPC codes: F16H61, B60K20, F16H59