WO1992018793A1

WO1992018793A1 - Gearshift

Info

Publication number: WO1992018793A1
Application number: PCT/FI1992/000109
Authority: WO
Inventors: Erkki SAARIJÄRVI
Original assignee: Mäkilä, Matti
Priority date: 1991-04-09
Filing date: 1992-04-09
Publication date: 1992-10-29
Also published as: FI89829C; FI911689A; EP0578722A1; AU1581892A; FI89829B; FI911689A0

Abstract

The invention relates to a gearshift for transmitting a continuous drive by way of three gear ratios, wherein the power extracted from a motor is automatically controlled through different gear ratios according to a required application. The torque supplied by a power source is delivered to a bevel wheel type of centre boss (2). The torsional force of the lowest, mechanical gear ratio is delivered through the action of an overrunning clutch (8A) to a planetary gear (60), the gear ratio being selected according to a required application. The torque of a so-called intermediary gear is delivered hydrodynamically by way of a fluid clutch (40) to a collecting planetary gear (50) at a gear ratio suitable for a given application. The torque of a so-called direct gear is delivered mechanically by way of a planetary support (18) included in planetary gear (60) to a directly torque-delivering shaft (20). All three gear ratios participate in the transmission of torque simultaneously - either actively or passively.

Description

Gearshift

The present invention relates to a gearshift for trans¬ mitting a continuous drive by way of three gear ratios, wherein the power extracted from a motor at any given time is controlled automatically through different gear ratios according to a required application, said gear¬ shift comprising a body member serving as a gearshift housing, an input shaft and an output shaft, said shafts having a common centre axis, a power supply gear, a fluid clutch or a means having similar qualities, as well as a first planetary gear, a second planetary gear, the centre axes of sun wheels included in said planetary gears coinciding with said centre axis.

An object of the invention is to provide a gearshift as described above and particularly a gearshift which re¬ quires no sensors, governors or locking keys.

The object is achieved according to the invention and the invention is characterized in that

- the input shaft is adapted to transmit the rotating motion supplied by a power source to sun wheels in¬ cluded in the planetary gears,

- power transmission from the gearshift input shaft to sun wheels is arranged through the intermediary of an overrunning clutch or a like in a manner that the speed of rotation of said sun wheels is at least equal to that of the input shaft,

- a sun wheel included in first planetary gear and a sun wheel included in second planetary gear are coupled non-rotatably to each other,

- the input shaft is adapted to transmit the rotating motion supplied by a power source with the aid of a power supply gear to a pump wheel included in a fluid clutch or a means having similar qualities and to a planetary support included in first planetary gear,

- a turbine disc included in the fluid clutch or means having similar qualities is coupled with a peripheral disc included in first planetary gear,

- a planetary support included in second planetary gear is coupled with the peripheral disc of first planetary- gear and with the gearshift output shaft,

- the planetary support of first planetary gear is coupled with the gearshift input shaft through the intermediary of an overrunning clutch or a like in a manner that the speed of rotation of said planetary support is limited not to exceed that of the input shaft,

- and the peripheral disc of second planetary gear is journalled to be rotatable relative to the centre axis and in such a way fixedly through the intermediary of an overrunning clutch or a like mounted on a station¬ ary body member in a manner that rotation of the peripheral disc is prevented in the direction oppo¬ site to the rotating direction of the gearshift out¬ put shaft.

According to a second embodiment of the invention, the above object is achieved and the invention is charac¬ terized in that

- the input shaft is adapted to transmit the rotating motion received from a power source to sun wheels in¬ cluded in planetary gears,

- power transmission from the gearshift input shaft to sun wheels is arranged through the intermediary of an overrunning clutch or a like in a manner that the speed of rotation of sun wheels is at least equal to that of the input shaft,

- the sun wheel of firts planetary gear and the sun wheel of second planetary gear are coupled non-rotatably to each other,

- the input shaft is adapted to transmit the rotating motion received from a power source with the aid of a power supply gear to a pump wheel included in a fluid clutch or a means having similar qualities and to the gearshift output shaft,

- a turbine disc included in the fluid clutch or means having similar qualities is coupled with a planetary support included in first planetary gear,

- a planetary support included in second planetary gear is coupled with the peripheral disc of first planetary gear and with the gearshift output shaft,

- a turbine disc included in the fluid clutch or means having similar qualities is coupled with the gear¬ shift input shaft through the intermediary of an over¬ running clutch or a like in a manner that the speed of rotation of turbine disc is limited not to exceed that of the input shaft,

- and the peripheral disc of second planetary gear is journalled to be rotatable relative to the centre axis and through the intermediary of an overrunning clutch or a like in such a way fixedly relative to a station¬ ary body member that rotation of the peripheral disc is prevented in the direction opposite to the rotating direction of the gearshift output shaft.

A torque supplied by the power source is delivered to a bevel gear type or a cylindrical gearwheel type or some other type of appropriate centre boss or to a com¬ ponent otherwise suitable for the distribution of tor¬ que. The torsional force of the lowest, mechanical gear ratio is delivered by means of an overrunning clutch or some other device operating on a similar principle to a planetary gear or a transmission unit operating on some other similar principle, the gear ratio being selected according to a required applica¬ tion. The torque of a so-called intermediary gear passes hydrodynamically through the action of a fluid clutch or a means having similar properties over to a collecting planetary gear at a gear ratio suitable for a given application. The torque of a so-called direct gear passes mechanically over to a shaft directly delivering the torque. All three gear ratios partici¬ pate in the transmission of torque simultaneously - either actively or passively. This way the power ex¬ tracted from a power source can be transmitted at an optimal gear ratio to a particular service.

The invention will now be described in more detail by way of an example with reference made to the accompany¬ ing drawings, in which

fig. 1 shows a schematic cross-section of a gearshift according to a first embodiment of the invention.

Fig. 2 shows a schematic cross-section of a gearshift according to a second embodiment of the inven¬ tion.

The main components of a gearshift shown schematically in figs. 1 and 2 include a gearshift input shaft 1 connected to a power source through the intermediary of a clutch (not shown) , a power supply gear 30, a fluid clutch 40, a first planetary gear 50, a second planetary gear 60, a gearshift output shaft 20, as well as a body member 22 (only partially shown) , mounted non-rotatably relative to the power source and serving as a gearshift housing. The shafts 1, 20 have a common centre axis 21, the gear¬ shift components being journalled in a per se known fashion to be rotatable relative to said axis.

The input shaft 1 is provided with a power supply gear 30 whose centre boss in indicated by reference numeral 2. In the solutions shown in figs. 1 and 2, said power supply gear 30 is of a bevel gear type and generally includes an even number, usually 2 or 4 , of small bevel wheels 3 journalled perpendicularly for free rotation relative to shaft 1. The large bevel wheels included in power supply gear 30 are indicated by reference numerals 4A and 4B and their axis of rotation coincides with gearshift centre axis 21.

The number of planetary wheels included in planetary gear 50 is usually at least 3 and those are indicated with reference numeral 12, a peripheral disc is shown at 11, a planetary support is shown at 14 and a sun wheel at 13. Accordingly, the planetary wheels in¬ cluded in planetary gear 60 are indicated with refer¬ ence numeral 17, a peripheral disc is shown at 15, a planetary support at 18 and a sun wheel at 16.

A pump wheel 6 and, a turbine disc 7 included in fluid clutch 40 are journalled rotatably relative to gearshift centre axis 21. The fluid clutch 40 can be replaced by some other means of similar qualities, e.g. a torque converter or an electromagnetic clutch.

The above describes common features found in the gear¬ shifts shown in figs. 1 and 2.

The exemplatory design shown in fig. 1 will now be de¬ scribed in more detail. The input shaft 1 , and especially its extension shown by reference numeral 9 , is adapted to transmit the ro¬ tating motion received from a power source to sun wheels 13, 16 included in planetary gears 50, 60. Sun wheels 13, 16 are coupled non-rotatably to each other.

Power transmission from gearshift input shaft 1 to sun wheels 13, 16 is effected through the intermediary of an overrunning clutch 8A or a like in a manner that the speed of rotation of sun wheels 13, 16 is always at least equal to that of input shaft 1.

The input shaft 1 is also adapted to transmit the rota¬ ting motion received from a power source with the assist¬ ance of power supply gear 30 to a pump wheel 6 included in fluid clutch 40 and to a planetary support 14 in¬ cluded in first planetary gear 50. Said pump wheel 6 is coupled with a bevel wheel 4B included in power supply gear 30 and planetary support 14 is coupled with a bevel wheel 4B included in power supply gear 30.

A turbine disc 7 included in fluid clutch 40 is coupled with a peripheral disc 11 included in first planetary gear 50.

A planetary support 18 included in second planetary gear 60 is coupled with said peripheral disc 11 of first planetary gear 50 and with gearshift output shaft 20.

The planetary support 14 of first planetary gear 50 is coupled with gearshift input shaft 1 , and particularly with its extension 9, through the intermediary of over¬ running clutch 8B or a like in a manner that the speed of rotation of planetary support 14 is limited not to exceed that of input shaft 1. A peripheral disc 15 included in second planetary gear 60 is rotatably journalled relative to centre axis 21 and in such a way fixedly through the intermediary of an overrunning clutch 19 or a like mounted on station¬ ary body member 22 that the rotation of peripheral disc 15 is prevented in the direction opposite to the rotating direction of gearshift output shaft 20.

The exemplatory design shown in fig. 2 will now be de¬ scribed in more detail.

The input shaft 1 is adapted to transmit the rotating motion received from a power source to sun wheels 13, 16 included in planetary gears 50, 60. Said sun wheels 13, 16 is coupled non-rotatably to each other and jour¬ nalled rotatably relative to output shaft 20.

Power transmission from gearshift input shaft 1 to sun wheels 13, 16 is effected through the intermediary of an overrunning clutch 8B or a like in a manner that the speed of rotation of sun wheels is always at least equal to that of input shaft 1. In the example of fig. 2 this is effected by using a cylindrical transmission shaft extension 9 ' mounted on the end of transmission shaft 1 and on the end of small bevel wheels 3 included in power supply gear 30. In this case, an overrunning clutch 8A is fitted between said extension 9 ' and a cylindrical projection 23 common to sun wheels 13, 16.

The input shaft 1 is adapted to transmit the rotating motion received from a power source by means of a power supply gear 30 to a pump wheel 6 included in fluid clutch 40 and to gearshift output shaft 20. Said pump wheel 6 is coupled with a bevel wheel 4B included in power supply gear 30 and said output shaft 20 with a bevel wheel 4A included in power supply gear 30.

A turbine disc 7 included in fluid clutch 40 is coupled with a planetary support 14 included in first planetary gear 50.

A planetary support 18 included in second planetary gear 60 is coupled with a peripheral disc 11 included in first planetary gear 50 and with gearshift output shaft 20.

Said turbine disc 7 of fluid clutch 40 is coupled with gearshift input shaft 1 through the intermediary of overrunning clutch 8B or a like in a manner that the speed of rotation of turbine disc 7 is limited not to exceed that of input shaft 1. Said overrunning clutch 8B is fitted between the cylindrical extension 9 ' of transmission shaft 1 and the turbine disc 7 or the planetary support 14 serving as an extension thereof.

A peripheral disc 15 included in second planetary gear 60 is journalled rotatably relative to centre axis 21 and in such a way fixedly through the intermediary of an overrunning clutch 19 or a like mounted on a station¬ ary body member that the rotation of peripheral disc 15 is prevented in the direction opposite to the rotating direction of gearshift output shaft 20.

A gearshift according to the invention includes three gear ratios for transmitting a continuous drive forward as well as a separately switchable reverse gear (not shown) . All three automatically controlled gear ratios participate in the transmission of torque simultaneous¬ ly - either actively or passively. The power trans¬ mission routes - paths I, II and III - at various gear ratios will be discussed later in connection with the description of the gearshift operating principle.

Prior to studying more closely the operation of a gear¬ shift, a brief reference is made to the prior known characteristics of fluid clutch 40 which are important in view of the operation of a gearshift according to the invention:

1. At low speeds of rotation of pump wheel the torque transmission ability is low.

2. As the difference in speeds of rotation between pump wheel and turbine disc increases, the torque transmission ability increases and, inversely, as the difference in speeds decreases, the torque trans¬ mission ability decreases.

3. A high speed of rotation for pump wheel means a high torque transmission ability regardless of the speed of rotation of turbine disc.

4. Slipping of fluid clutch.

The following description deals with the operation of a gearshift shown in fig. 1.

As the action commences, the power delivered by a motor translates through gearshift input shaft 1 to the centre boss 2 of power supply gear 30. From centre boss 2 the power proceeds by means of- shaft 9 to overrunning clutch 8A. The overrunning clutch 8A translates the power to sun wheels 13 and 16 which are linked together. The sun wheel 16 translates the power to planetary wheels 17, which provide a peripheral disc 15 with an oppositely directed rotating force. This is prevented by an over¬ running clutch 19. Thus, the power of a motor trans¬ lates through the transmission of a planetary support 18 to gearshift output shaft 20 at the very gear ratio selected for planetary gear 60.

At the same time as path I commences its action, said paths II and III are also activated.

The small bevel wheels 3 included in centre boss 2 of power supply gear 30 rest against large bevel wheels 4A and 4B, with the one shown at 4A being coupled to planetary support 14 and the one shown at 4B to pump wheel 6 of fluid clutch 40.

The support moment for pump wheel 6 of fluid clutch 40 is now provided by planetary support 14 rotating faster relative to output shaft 20.

When planetary support 14 and its associated bevel wheel 4A have reached the speed of rotation of a power source, the overrunning clutch 8B prevents the speed of rotation from exceeding that of shaft 9. The trans¬ mission of power through the intermediary gear ceases at the time said overrunning clutch 8B limits the in¬ crease of the speed of rotation. Thus, bevel wheel 4A provides an a further support moment for bevel wheel 4B, which is coupled with pump wheel 6 of fluid clutch 40. The transmission of power is now hydrodynamically directed through fluid clutch turbine disc 7 to a peri¬ pheral disc 11, which is connected by way of planetary support 18 to output shaft 20.

When the speed of rotation of output shaft 20 begins to rise in relation to shaft 1 , whose speed of rotation is maintained constant just like those of bevel wheel 4A and planetary support 14, the moment opposing peri¬ pheral disc 15 disappears and the latter commences ro¬ tation in the same direction as a power source by means of overrunning clutch 19. At the same time, the speed of rotation of sun wheels 13 and 16 begins to decline and when the difference in rotating speeds of pump wheel 6 and the turbine disc of fluid clutch 40 has equalized, the gear ratio will be 1:1.

The following describes the operation of a gearshift shown in fig. 2.

As the action commences, the power delivered by a motor translates through gearshift input shaft 1 to the centre boss 2 of power supply gear 30. To said centre boss 2 is coupled a centre boss 9 ' included in a dual overrung clutch 8A, 8B. The overrunning clutch 8A translates the power to sun wheels 13 and 16, which are linked together and whose speed of rotation is thus al¬ ways at least equal to that of the power source.

The sun wheel 16 rotates planetary wheels 17, resulting in the opposite rotating direction for peripheral disc 15. This is prevented by an overrunning clutch 19. The power translates now through a planetary support 18 to output shaft 20 at the same gear ration which is selected for planetary gear 60.

At the same time as path I commences its action, also paths II and III are activated.

Small bevel wheels 3 rest or lean against large bevel wheel 4A, coupled to output shaft 20 which now rotates at the speed of rotation provided by the lowest gear ratio. The pump wheel 6 of fluid clutch 40 and the large bevel wheel 4B are now rotating through the action of support moment provided by large bevel wheel 4A. The power from fluid clutch clutch pump wheel 6 translates hydro- dynamically to fluid clutch turbine disc 7, which is coupled to planetary support 14. The speed of rotation of planetary support 14 begins to increase and, thus, the speed of rotation of sun wheels 13 and 16 rises above that of the power source. The peripheral disc 15 is still subjected to an opposite torque, which is eliminated by overrunning clutch 19.

When the planetary support 14 reaches the speed of ro¬ tation of a power source, the increase of its speed of rotation in relation to the power source is prevented by means of overrunning clutch 8B. The transmission of power through path II comes to an end. At this time, the opposite torque disappears from peripheral disc 15 and its speed of rotation begins to rise in relation to the decline of the speed of rotation of sun wheels 13 and 16.

When there is a difference in speeds of rotation be¬ tween the pump wheel 6 and the turbine disc 7 of fluid clutch 40, the support moment translates from bevel 4A to bevel wheel 4B and, since the speed of rotation of planetary support 14 can no longer increase, the differ¬ ence in speeds of rotation between pump wheel 6 and turbine disc 7 of fluid clutch 40 equalizes through bevel wheel 4A to output shaft 20. When the speed of rotation of all components has equalized to be the same as that of the power source, the gear ratio will be 1:1 and, within the interior of this gearshift, there is no component rotating in relation to any other component of the apparatus but only around axis 21 and relative to housing 22.

Claims

1. A gearshift for transmitting a continuous drive by way of three gear ratios, wherein the power extracted from a motor at any given time is controlled automatic¬ ally through different gear ratios according to re¬ quired application, said gearshift comprising a body member (22) serving as a gearshift housing, an input shaft (1) and an output shaft (20) , said shafts having a common centre axis (21) , a power supply gear (30) , a fluid clutch or a means having similar qualities (40) , as well as a first planetary gear (50) and a second planetary gear (60) , the centre axes of sun wheels (13, 16) included in said planetary gears coinciding with said centre axis (21) , whereby

- input shaft (1) is adapted to transmit the rotating motion supplied by a power source to sun wheels (13, 16) included in planetary gears (50, 60) ,

- power transmission from gearshift input shaft (1) to sun wheels (13, 16) is effected through the inter¬ mediary of an overrunning clutch (8A) or a like in a manner that the speed of rotation of sun wheels (13, 16) is at least equal to that of input shaft (1) ,

- sun wheel (13) included in first planetary gear (50) and sun wheel (16) included in second planetary gear

(60) are coupled non-rotatably to each other,

- input shaft (1) is adapted to transmit the rotating motion supplied by a power source through the action of power supply gear (30) to a pump wheel (6) included in fluid clutch or means (40) having similar qualities,

- a planetary support (18) included in second planetary gear (60) is coupled with a peripheral disc (11) in¬ cluded in first planetary gear (50) and with gearshift output shaft (20) ,

- a planetary support (14) included in first planetary gear (50) is coupled with gearshift input shaft (1) through the intermediary of an overrunning clutch (8B) or a like in a manner that the speed of rotation of planetary support (14) is limited not to exceed that of input shaft (1 ) , and - a peripheral disc (15) included in second planetary gear (60) is journalled to be rotatable relative to centre axis (21) and through the intermediary of an overrunning clutch (19) or a like in such a way fixed¬ ly relative to stationary body member (22) that the rotation peripheral disc (15) is prevented in the direction opposite to the rotating direction of gear¬ shift output shaft (20), c h a r a c t e r i z e d in that said input shaft (1) is adapted to transmit the rotating motion supplied by a power source through the action of power supply gear (30) to planetary support (14) of first planetary gear (50) , and that a turbine disc (7) included in said fluid clutch or means (40) of similar qualities is coupled with peripheral disc 11 of first planetary gear (50) (fig. 1).

2. A gearshift for transmitting a continuous drive by way of three gear ratios, wherein the power extracted from a motor at any given time is controlled automatic¬ ally through different gear ratios according to a re¬ quired application, said gearshift comprising a body member (22) serving as a gearshift housing, an input shaft (1) and an output shaft (20) , said shafts having a common centre axis (21) , a power supply gear (30) , a fluid clutch or a means having similar qualities (40) , as well as a first planetary gear (50) and a second planetary gear (60), the centre axes of sun wheels (13, 16) included in said planetary gears coinciding with said centre axis (21) , whereby

- input shaft (1 ) is adapted to transmit the rotating motion supplied by a power source to sun wheels (13, 16) included in planetary gears (50, 60) ,

- sun wheel (13) included in first planetary gear (50) and sun wheel (16) included in second planetary gear (60) are coupled non-rotatably to each other,

- input shaft (1) is adapted to transmit the rotating motion supplied by a power source through the action of power supply gear (30) to a pump wheel (6) in¬ cluded in fluid clutch or means (40) of similar qua¬ lities and to gearshift output shaft (20) ,

- a turbine disc (7) included in fluid clutch or means

(40) of similar qualities is coupled with a planetary support (14) included in first planetary gear (50) ,

- said turbine disc (7) included in fluid clutch or means (40) of similar qualities is coupled with gear¬ shift input shaft (1 ) through the intermediary of an overrunning clutch (8B) or a like in a manner that the speed of rotation of turbine disc (7) is limited not to exceed that of input shaft (1 ) , and

- a peripheral disc (15) included in second planetary gear (60) is journalled to be rotatable relative to centre axis (21) and in such a way fixedly through the intermediary of an overrunning clutch (19) or a like mounted on a stationary body member (22) in a manner that the rotation of peripheral disc (15) is prevented in the direction opposite to the rotating direction of gearshift output shaft (20) , c h a r - a c t e r i z e d in that a bevel wheel (4A) included in power supply gear (30) is directly connected to the en_d of gearshift output shaft (20) facing towards said gearshift (fig. 2) .