GB1605068A

GB1605068A - Transmission for a frameless tractor

Info

Publication number: GB1605068A
Application number: GB2394978A
Authority: GB
Original assignee: Massey Ferguson Services NV
Current assignee: Massey Ferguson Services NV
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-12-16
Also published as: CA1101694A; AR221878A1; ES243647Y; FR2427216B1; FR2427216A1; ES243647U

Description

(54) TRANSMISSION FOR A FRAMELESS TRACTOR (71) We, MASSEY-FERGUSON SER VICES N.V., Abraham de Veerstraat 7A, Curacao, Netherlands Antilles, a company organised under the laws of Netherlands Antilles, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates generally to change speed transmission and more particularly to a change speed transmission for a frameless tractor of the type wherein the transmission housing is a structural component of the tractor.

It has long been recognized that differing transmissions may be desired by the customer's of self-propelled equipment. Thus, one customer may want a transmission having only a few differing speed ratios while another may want a large number of speed ratios. In the truck industry this has been accomplished by offering a basic transmission including a housing to which additional transmission housing may be added. In the tractor industry this is generally not practical as most tractors are of the frameless type wherein the transmission housing, engine block and rear or centre housing form structural components of the tractor. Therefore, in the tractor trade it has been common to factory install various change gear mechanisms within a standard housing. As most tractors are built for inventory it is necessary to accurately predict the customers requirement when building these tractors if an excessive inventory of one form of tractor transmission is to be avoided.

It is an object of the present invention to provide a transmission which is suitable for use in a frameless tractor and which allows ready alteration of the number of speed ratios provided.

According to the present invention there is provided a transmission for a frameless tractor for connecting drive and driven members, the transmission comprising a first change gear mechanism including first and second parallel shafts, one of which is for connection to the driven member; a housing having side walls which are adapted to encompass the first change gear mechanism, and an inwardly extending annular flange carried by the side walls; a support structure removably secured to the annular flange and rotatably supporting an end portion of the first shaft; and a second change gear mechanism connected in series with the first change gear mechanism and carried by the support structure, the second change gear mechanism including a third shaft for connection with the drive member, the third shaft being supported in coaxial alignment with the first shaft, and a forward reverse mechanism which is arranged so that the selection of forward and reverse drive conditions is effected solely by a coupler which is mounted on the third shaft for longitudinal movement therealong.

It is possible, for example, for a tractor dealer or the manufacturer to relatively easily change the speed ratios of a tractor which has previously been fully assembled and which includes a transmission in accordance with the present invention. This can be accomplished by substituting one second change gear mechanism for another with a different number of ratios.

In a transmission in accordance with the present invention the first change gear mechanism can be of a relatively simple construction since it is required to provide speed ratios in one direction only as the second readily detachable and interchangeable change gear mechanism provides the reversing function and may also include additional speed ratios.

Thus, for example, the second change gear mechanism might simply comprise a forward/reverse mechanism when the trac tor was initially assembled and a tractor dealer could double the number of speed ratios offered by the transmission by changing this initial second change gear mechanism for a second change gear mechanism which includes a forward/reverse mechanism and a two speed planetary gear set.

The second change gear mechanism may include a shift rail detachably connected to a shifting mechanism. Conveniently the shifting mechanism may be disposed to one side of the first change gear mechanism.

One embodiment of the present invention will now be described, by way of example only with reference to the accompanymg drawings in which: Figure 1 is a side view of a frameless tractor in which the principles of the present invention are incorporated; Figure 2 is a sectional view of one transmission option; Figure 3 is an enlarged view of a portion of the transmission shown in Figure 2; Figure 4 is a section taken generally along the line 4-4 in Figure 3; Figure 5 is a section taken generally along the line 5-5 in Figure 4, and Figure 6 is a view similar to Figure 3 showing a second transmission option.

Referring first to Figure 1, a frameless tractor is illustrated, the tractor being indicated generally at 10 and including an engine 12, a transmission indicated generally at 14, the transmission including a housing 16, a rear or centre housing 18, and an axle housing 20. Front and rear wheels 22, 24 are mounted on the tractor in a conventional manner. As can be seen from Figure 1 the engine 12, transmission housing 16 and centre housing 18 form structural support members for the tractor and therefore this type of tractor is generally referred to as a frameless tractor.

In accordance withe the principles of this invention first and second change gear mechanisms, indicated generally at 26 and 28, (Figure 2) are coupled to each other within the transmission housing. The first change gear mechanism as illustrated is of a type giving eight differing speed ratios. The second change gear mechanism is of a type including a forward/reverse mechanism, and it may include additional speed ratios. Thus, in the embodiment illustrated in Figure 2 the second change gear mechanism includes a forward/reverse mechanism as well as mechanism for providing two additional speed ratios to the input of the first change gear mechanism 26, thereby providing a transmission having 16 speeds. Differing second change gear mechanisms may be employed and a second version is illustrated in Figure 6. In order to provide for the substitution of one change gear mechanism for another it has been necessary to design the first and second change gear mechanisms and the housing in a special manner.

To this end the first change gear mechanism 26 is provided with a first hollow shaft 30 and a second two piece shaft 34, the rear end of the first shaft 30 being rotatably journaled in the rear end wall 32 of the housing 34 being rotatably journaled in a bearing plate 35 which is in turn carried by the rear wall 32. A plurality of intermeshing gear sets 36 are carried by the first-and second shafts 30, 34 and are selectively interconnectable to transmit power from one shaft to the other. One manner in which the gears 36 may be mounted on the shafts 30, 34 is illustrated in U.S. Patent 1 391 854.

The second shaft assembly 34 is divided into forward and rear portions 38, 40, respectively, the forward end of the rear portion 40 being journaled by bearings 42 carried within a cylindrical recess on the rear end of the forward portion 38. The forward portion 38 may be referred to as a counter shaft, and the rear portion 40 as an output shaft. The output shaft 40 is coupled to a driven member (not shown). The forward end of the counter shaft 38 is carried by a bearing 44 which is in turn supported by a first flange 46 which extends inwardly from the generally cylindrical side walls 48 of the housing 16. An additional flange 50 is provided between the first flange 46 and the rear wall 32, the additional flange 50 carrying a further bearing 52 which rotatably supports a rear portion of the counter shaft 38.

In order to removably mount a second change gear mechanism within the housing, the housing 16 is provided with an inwardly extending annular flange 54. A support structure indicated generally at 56 is removably secured to the second flange 54. In the embodiment illustrated in Figures 2 and 3 the support structure 56 is formed of two parts which shall be referred to as the front cover 58 and the support frame 60. The front cover 58 is provided with a radially outwardly extending circular flange 62 which is secured to the annular flange 54 by bolts 64 or the like. The support frame 60 has a radius less than that of the annular support flange 54 and is secured to the front cover 58 by cap screws 66. The front cover and support frame 58, 60 co-operate with the rear wall 32 to form a fluid reservoir within the housing 16. In addition, the support frame 60, which is rigidly mounted within the housing, is utilized to support the forward end of the main shaft 30. To this end, a bearing support 68 which carries a bearing 70 is secured in place by bolts 72.

The forward end of the first shaft 30 is journaled within the bearing 70.

The support frame 60 carries additional bearings 74 and 76 in which is journaled a hollow third shaft 78. Rotatably mounted on the third shaft are spaced apart forward and reverse gears 80, 82. A shiftable coupler 84 is keyed to the shaft 78 and may be shifted axially of the shaft to drivingly interconnect either the forward gear 80 with the shaft 78 or the reverse gear 82 with the shaft 78. The coupler is caused to be shifted by a shift rail 83 and fork 85. The shift rail is carried by the support member 56 for axial sliding movement. The gear 80 is at all times in constant mesh with a gear 86 carried by the forward end of the counter shaft 38. The support structure 56 additionally carries a stub shaft 88 (Figures 4 and 5) upon which is mounted a reverse idler 90 having a first toothed portion 92 which is constantly in mesh with the teeth on gear 82, and a second toothed portion 94 which is constantly in mesh with the teeth on gear 86.

Mounted forwardly of the forward/reverse gear mechanism is a 2-speed planetary gear set indicated generally at 96, which gear set along with the forward/reverse mechanism completes the second change gear mechanism 26. The planetary gear set includes a hollow input shaft 98 the forward end of which is coupled to a drive member such as a tractor clutch plate (not shown).

The rear end of the input shaft 98 is supported by a bearing 100 disposed within an aperture of the clutch release bearing carrier 102 which is in turn secured to the front cover 58 by fasteners 104. A ring gear 106 is secured to the input shaft 98 by bolts 108. A hydraulically operated clutch pack 110 may be utilized to couple the ring gear 106 to a planet carrier 112. Thus, when fluid is introduced into the chamber 114 behind the piston 116, the clutch pack 110 will be engaged thereby locking the planet carrier 112 to the ring gear 106. The planet carrier is provided with a plurality of axially extending stub shafts 118 on which are mounted planet gears 120. The teeth 112 on the ring gear 106 and the teeth 124 on a sun gear 126 are in constant mesh with the teeth on the planet gears 120. The planet carrier 112 is coupled directly to the third shaft 78 upon which the forward/reverse gear mechanism is mounted, and the sun gear 126 is journaled for rotation about the shaft 78. A clutch disc 128 is secured to the sun gear, which clutch disc may be utilized to hold the sun gear from rotation. To this end compression springs 130 are disposed in suitable recesses in the front cover 58, the springs 130 acting against a pressure plate 132 to normally bias the clutch disc 128 into engagement with a flat surface on the support frame 60. The clutch disc 128 may be disengaged by introducing fluid under pressure into chamber 134 to cause piston 136 to engage the pressure plate 132 and move the plate 132 away from the clutch disc 128 and flat surface. The fluid circuit for operating the planetary gear set 96 is illustrated somewhat schematically in Figure 2 and includes a pump 138, fluid reservoir 140, valve 142, and manual control lever 144.

When the valve is in the position illustrated in Figure 2 fluid from the pump 138 will be returned directly to the reservoir through line 146. In this position the springs 130 will hold the clutch disc 128 against the flat surface of the housing 60. When the manual control lever 144 is shifted to its other position (not illustrated) fluid from the pump 138 will be introduced into line 148 and thence into chambers 114 and 134 to cause the piston 136 to disengage the pressure plate 132 and piston 116 to engage the hydraulically operated clutch pack 110. The preload of springs 130 is so designed that when fluid is introduced into the chambers 134 and 114 the hydraulically operated clutch pack 110 will be partially engaged prior to the full disengagement of the first clutch 128. In the even that the clutch 128 became disengaged before the clutch 110 became engaged it would be possible for power flow to be interrupted from the shaft 98 to the shaft 78. By employing springs 130 having a certain preload characteristic it is possible to insure continuous power flow as the planetary gear set is being shifted from its high speed ratio when clutch 128 is engaged to its low speed ratio when clutch pack 110 is engaged, and vice versa.

In the embodiment shown in Figures 2 to 5 the transmission 14 has 16-speed ratios. In the embodiment illustrated in Figure 6, which will now be described, the 2-speed planetary input portion of the second change gear mechanism is eliminated and therefore the transmission 14 is capable of only eight forward speeds. Before describing Figure 6 in detail it should be observed that some of the components of the second change gear mechanism illustrated in Figure 6 and indicated generally at 150 are identical to components illustrated in Figures 2 to 5, and these components will be indicated by the same reference numerals. In addition, while a first change gear mechanism is illustrated having 8-speeds, other first change gear mechanisms could be employed having a differing number of speeds, such as 4, 6 etc.

The second change gear mechanism 150 of the type illustrated in Figure 6 includes a combined front cover and support frame 152 provided with an annular flange 154 which may be secured to the annular second flange 54 of the transmission housing 16 by bolts 64. A bearing 70 is carried by a rear portion of the support 152 and is secured in place by screws 156 and a bearing retainer 158. The forward end of the main shaft 30 is journaled within the bearing 70. An input shaft 160, whose forward end is coupled to a drive member such as a tractor clutch, has its rear end coupled directly to the third shaft 78.

The forward end of the hollow third shaft 78 is supported by a spacer 162 which is in turn supported by a bearing 164 carried by the support frame 152. The rear end of the shaft 78 is also supported by a bearing 166 carried by the support frame 152. A forward/ reverse mechanism including forward and reverse gears 80, 82 and coupler 84 are mounted about the shaft 78, the gear 80 being in constant mesh with gear 86 on the forward end of counter shaft 38 and the gear 82 being in constant mesh with a reverse idler 90. A fork 85 engages the coupler 84 and is shifted by a shift rail (not shown) which is carried by the support frame 152.

By designing the transmission in the manner indicated above it is possible to utilize the same basic or first change gear mechanism 26 with a variety of second change gear mechanisms which may provide, for example, only a forward/reverse gear mechanism of the type illustrated at 150 in Figure 6, a 2-speed forward/reverse mechanism of the type illustrated at 28 in Figures 2 to 5, or by other input mechanisms such as, for example, a 3-speed forward/ reverse mechanism of the type illustrated in U.K. Patent 1 399 373. The manner of converting a tractor from the 16-speed transmission of the type illustrated in Figure 2 to the 8-speed transmission of the type illustrated in Figure 6 will now be described.

It is first necessary to separate the transmission housing 16 from the engine 12 and to move these parts apart. To this end, it would be necessry to dis-connect all lines, controls, etc., which extend between the engine 12 and housing 16. After this has been done bolts 168 (Figure 1) which secure the housing 16 to the engine must be removed to permit the front and rear halves of the tractor to be moved apart. The power take-off shaft 170 which extends through the hollow shafts 98, 78 and 30 is then removed.

(The front end of the PTO shaft is connected to the engine flywheel by a spline.) After this has been done it is necessary to remove various lubrication lines (not illustrated) and to then remove the clutch release bearing carrier 102, the saddle assembly 172, the clutch release lever 174, and the clutch cross shaft 176. As the shift rail 83 and fork 85 for the forward/reverse mechanism are carried by the structure 56 it is necessary that the shift cover 182 be removed from the right side of the transmission housing in order to disengage the reverse actuator 184 from the forward reverse saddle 186 carried at the rear end of the shift rail 83. While the mechanism for operating the reverse actuator 184 is not illustrated it should be observed that the reverse actuator 184 may be carried at one end of a rock arm, the other end of which is connected to a rock shaft which may be rotatably mounted in the shift cover 182.

The shaft column and controls for the other shift rails 188, as well as the mechanism for operating the reverse actuator 184, are positioned to one side of the first change gear mechanism 26.

When the assembly 28 is being removed it is essential that it be pulled out axially approximately two inches to cause the front ends of shift rails 188 and the rear end of lubrication tube 190 to be disconnected from their associated recesses. The assembly is then rotated counterclockwise approximately 1/8 of a turn and is then pulled from the transmission housing 16. To install the assembly 150 in the housing 16 the procedure outlined above is followed in reverse order.

It will be appreciated from the above description that not only does the present invention provide a simple and efficient means of extending the ratio range of the first change gear mechanism and providing a forward/reverse facility but by removably supporting the second change gear mechanism as a whole within the housing removal of the second gear change mechanism is greatly fcilitated making easy adjustments of the overall ratio range of the transmission possible by the use of different second change gear mechanisms.

Further constructional details of the transmission described above are the subject of our co-pending U.K. Patent Application Number 23948/78 Serial No 1605067 and the method by which the number of speed ratios of this transmission can be changed are the subject of our co-pending U.S. Patent Application Number 23951/78 Serial No 160 069.

WHAT WE CLAIM IS: 1. A transmission for a frameless tractor for connecting drive and driven members, the transmission comprising a first change gear mechanism including first and second parallel shafts, one of which is for connection to the driven member; a housing having side walls which are adapted to encompass the first change gear mechanism, and an inwardly extending annular flange carried by the side walls; a support structure removably secured to the annular flange and rotatably supporting an end portion of the first shaft; and a second change gear mechanism connected in series with the first change gear mechanism and carried by the support structure, the second change gear mechanism including a third shaft for connection with the drive member, the third shaft being supported in co-axial alignment with the first shaft, and a forward/reverse mechanism which is arranged so that the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 160, whose forward end is coupled to a drive member such as a tractor clutch, has its rear end coupled directly to the third shaft 78. The forward end of the hollow third shaft 78 is supported by a spacer 162 which is in turn supported by a bearing 164 carried by the support frame 152. The rear end of the shaft 78 is also supported by a bearing 166 carried by the support frame 152. A forward/ reverse mechanism including forward and reverse gears 80, 82 and coupler 84 are mounted about the shaft 78, the gear 80 being in constant mesh with gear 86 on the forward end of counter shaft 38 and the gear 82 being in constant mesh with a reverse idler 90. A fork 85 engages the coupler 84 and is shifted by a shift rail (not shown) which is carried by the support frame 152. By designing the transmission in the manner indicated above it is possible to utilize the same basic or first change gear mechanism 26 with a variety of second change gear mechanisms which may provide, for example, only a forward/reverse gear mechanism of the type illustrated at 150 in Figure 6, a 2-speed forward/reverse mechanism of the type illustrated at 28 in Figures 2 to 5, or by other input mechanisms such as, for example, a 3-speed forward/ reverse mechanism of the type illustrated in U.K. Patent 1 399 373. The manner of converting a tractor from the 16-speed transmission of the type illustrated in Figure 2 to the 8-speed transmission of the type illustrated in Figure 6 will now be described. It is first necessary to separate the transmission housing 16 from the engine 12 and to move these parts apart. To this end, it would be necessry to dis-connect all lines, controls, etc., which extend between the engine 12 and housing 16. After this has been done bolts 168 (Figure 1) which secure the housing 16 to the engine must be removed to permit the front and rear halves of the tractor to be moved apart. The power take-off shaft 170 which extends through the hollow shafts 98, 78 and 30 is then removed. (The front end of the PTO shaft is connected to the engine flywheel by a spline.) After this has been done it is necessary to remove various lubrication lines (not illustrated) and to then remove the clutch release bearing carrier 102, the saddle assembly 172, the clutch release lever 174, and the clutch cross shaft 176. As the shift rail 83 and fork 85 for the forward/reverse mechanism are carried by the structure 56 it is necessary that the shift cover 182 be removed from the right side of the transmission housing in order to disengage the reverse actuator 184 from the forward reverse saddle 186 carried at the rear end of the shift rail 83. While the mechanism for operating the reverse actuator 184 is not illustrated it should be observed that the reverse actuator 184 may be carried at one end of a rock arm, the other end of which is connected to a rock shaft which may be rotatably mounted in the shift cover 182. The shaft column and controls for the other shift rails 188, as well as the mechanism for operating the reverse actuator 184, are positioned to one side of the first change gear mechanism 26. When the assembly 28 is being removed it is essential that it be pulled out axially approximately two inches to cause the front ends of shift rails 188 and the rear end of lubrication tube 190 to be disconnected from their associated recesses. The assembly is then rotated counterclockwise approximately 1/8 of a turn and is then pulled from the transmission housing 16. To install the assembly 150 in the housing 16 the procedure outlined above is followed in reverse order. It will be appreciated from the above description that not only does the present invention provide a simple and efficient means of extending the ratio range of the first change gear mechanism and providing a forward/reverse facility but by removably supporting the second change gear mechanism as a whole within the housing removal of the second gear change mechanism is greatly fcilitated making easy adjustments of the overall ratio range of the transmission possible by the use of different second change gear mechanisms. Further constructional details of the transmission described above are the subject of our co-pending U.K. Patent Application Number 23948/78 Serial No 1605067 and the method by which the number of speed ratios of this transmission can be changed are the subject of our co-pending U.S. Patent Application Number 23951/78 Serial No 160 069. WHAT WE CLAIM IS:

1. A transmission for a frameless tractor for connecting drive and driven members, the transmission comprising a first change gear mechanism including first and second parallel shafts, one of which is for connection to the driven member; a housing having side walls which are adapted to encompass the first change gear mechanism, and an inwardly extending annular flange carried by the side walls; a support structure removably secured to the annular flange and rotatably supporting an end portion of the first shaft; and a second change gear mechanism connected in series with the first change gear mechanism and carried by the support structure, the second change gear mechanism including a third shaft for connection with the drive member, the third shaft being supported in co-axial alignment with the first shaft, and a forward/reverse mechanism which is arranged so that the

selection of forward and reverse drive conditions is effected solely by a coupler which is mounted on the third shaft for longitudinal movement therealong.

2. A transmission according to claim 1 wherein the second change gear mechanism further includes a shift rail and a shifting mechanism, the shift rail being detachably connected to the shifting mechanism.

3. A transmission according to claim 2 wherein the shifting mechanism is disposed to one side of the first change gear mechanism.

4. A transmission according to claim 2 or claim 3 wherein the second shaft is longitudinally divisible into two independently rotatable shaft portions, and wherein intermeshing gear sets are supported by the first shaft and by both the two portions of the second shaft, and wherein the first change gear mechanism further includes shift rails generally parallel to the shift rail for the second change gear mechanism.

5. A transmission according to any one of claims 1 to 4 wherein the housing further includes an end wall remote from the annular flange, the end wall rotatably supporting end portions of the first and second shafts, and a flange disposed between the annular flange and the end wall for rotatably supporting the other end portion of the second shaft.

6. A transmission according to claim 5 wherein a fluid reservoir is defined within the housing between the support structure and annular flange at one end and the end wall at the other end.

7. A transmission according to any one of claims 1 to 6 wherein the forward/reverse mechanism drives a gear mounted on an end of the second shaft to provide the series connection between the first and second change gear mechanisms.

8. A transmission for a frameless tractor for connecting drive and driven members, the transmission comprising a first change gear mechanism including first and second parallel shafts, one of which is for connection to the driven member, and a plurlity of intermeshing gear sets carried by the first and second shafts and selectively operable to transmit power from one shaft to the other; a housing for the first change gear mechanism, the housing also serving as a tractor structural support and having side walls which are adapted to encompass the first change gear mechanism, an end wall rotatably supporting end portions for the first and second shafts, a first flange for rotatably supporting the other end portion of the second shaft, and an inwardly extending annular second flange carried by the side walls and disposed on the side of the first flange remote from the end wall; a support structure removably secured to the annular second flange and co-operating with the end wall to form a fluid reservoir therebetween, said support structure rotatably supporting the other end portion of the first shaft; and a second change gear mechanism connected in series with the first change gear mechanism and carried by the support structure, the second change gear mechanism including a third shaft for connection with the drive member, the third shaft being supported in co-axial alignment with the first shaft, a forward/reverse mechanism which is arranged so that the selection of forward and reverse drive conditions is effected solely by longitudinal movement of a coupler which is mounted on the third shaft for longitudinal movement there along, and a shift rail and fork interconnected with the longitudinally movable coupler and detachably connected with a shifting mechanism disposed to one side of the first change gear mechanism.

9. A transmission according to claim 1 constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.