CA1190831A - Tractor transmission - Google Patents

Tractor transmission

Info

Publication number
CA1190831A
CA1190831A CA000389031A CA389031A CA1190831A CA 1190831 A CA1190831 A CA 1190831A CA 000389031 A CA000389031 A CA 000389031A CA 389031 A CA389031 A CA 389031A CA 1190831 A CA1190831 A CA 1190831A
Authority
CA
Canada
Prior art keywords
gear
drive switching
backward
case
forward drive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000389031A
Other languages
French (fr)
Inventor
Takashi Yoshii
Yasuyuki Horii
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kubota Corp
Original Assignee
Kubota Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kubota Corp filed Critical Kubota Corp
Application granted granted Critical
Publication of CA1190831A publication Critical patent/CA1190831A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H63/00Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
    • F16H63/02Final output mechanisms therefor; Actuating means for the final output mechanisms
    • F16H63/24Final output mechanisms therefor; Actuating means for the final output mechanisms each of the final output mechanisms being moved by only one of the various final actuating mechanisms
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K17/00Arrangement or mounting of transmissions in vehicles
    • B60K17/04Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing
    • B60K17/06Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of change-speed gearing
    • B60K17/08Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of change-speed gearing of mechanical type
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H3/00Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/02Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
    • F16H3/08Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts
    • F16H3/14Gearings for reversal only
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H37/00Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/04Combinations of toothed gearings only
    • F16H37/042Combinations of toothed gearings only change gear transmissions in group arrangement
    • F16H37/043Combinations of toothed gearings only change gear transmissions in group arrangement without gears having orbital motion

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Structure Of Transmissions (AREA)
  • Arrangement Of Transmissions (AREA)
  • General Details Of Gearings (AREA)

Abstract

Abstract of the Disclosure A transmission for a tractor comprising a main chage-speed mechanism, an auxiliary change-speed mechanism, and a gear type backward-forward drive switching mecha-nism for transmitting power from an engine to a propelling system The main change-speed mechanism the gear type backward-forward drive switching mechanism and the auxiliary change-speed mechanism are arranged in a transmission case in the mentioned order in the forward to rearward direction of the tractor.

Description

33~

The present invention relates to tractor transmissions, and in particular to a transmission comprising a main change-speed mechanism, an auxiliary change-speed mechanism, and a gear type backward-forward drive switching mechanism for transrnitting powr from an engine to a propelling system.
2. Description of the Prior Art In conventional tractor transmissions comprising a main change-speed mechanism, an auxiliary change-speed mechanism, and a gear type backward-forward drive switching mechanism as described above, the gear type backward-forward drive switching mechanism is provided in one of the three fashions, namely combined into the main change-speed mechanism, disposed ~orwardly of the main change-speed mechanism, or disposed rearwardly of the auxiliary change-speed mechanism.
The case of the gear type backward-forward ~rive switch-ing mechanism being combined into the rnain change-speed mechanism is a mere remnant of the times when plural backward speeds were unnecessary to tractors as still are to ordinary motor vehicles. Such a construction cannot meet the require-ment of tractors to perform varied functions by utilizing plural backward speeds.
In order to meet this requirement, plural backward - 1 - ~, (3~1 speeds are now provided. A backward-forward drive switching mechanism to provide plural backward speeds without necessi-tating extensive rnodifications to the main change-speed, mechanism is in many instances disposed forwardly of the main change-speed mechanism to reverse the rotation of a transmission shaft prior to power input to the main change-speed mechanism. ~owever, this arrangement involves a change gear operation prior to reduction of the engine speed by the main change-speed mcchanism, and therefore has the disadvantage of having to effect gear meshing under high speed ro-tation which lacks in smoothness.
It has also been practised to dispose the backward-forward drive switching mechanism rearwardly of the main and auxiliary change-speed mechanisms. In this instance, a hand lever for operating the switch mechanism is provided close to a hand lever for operating the main change-speed rnechanisrn adjacent the driver's seat. It has the disadvan-tage of re~uiring a long interlocking rnechanism operatively connecting the backward-forward drive swi-tching mechanism to its hand lever.

Summary of the Inven-tion The object of this invention is to eliminate the draw-backs of the prior ar-t constructions described above and to arrange the gear type backward-forward drive switching mechanism in a rational manner which is operable by a sirnple B3~

interlocking mechanism and e~fects a smooth backward-forward drive switching.
In order to achieve the above object, a transmission for a tractor according to the present invention comprises a main change-speed mechanism9 an auxiliary change-speed mechanism, and a gear type backward-forward drive switching mechanism for transmitting power from an engine to a propel-ling system, wherein the main change-speed mechanism, the gear type backward-forward drive switching mechanism, and the auxiliary change-speed mechanism are arranged in a trans-mission case in the mentioned order in the forward to rearwarddirection of the tractor.
More particularly, the construction according to the present invention in which the main change speed mechanism, the gear type backward-forward drive switching mechanism, and the auxiliary change-speed mechanism are arranged in a transmission case in the mentioned order in the forward to rearward direction of the tractor, results in the following advantages over prior art constructions. Since the backward-forward drive switching mechanism is disposed rearwardly of the main change-speed mechanism, gear shifting is carried out under a low speed condition provided by the main change-speed mechanism thereby realizing a smoother backward-forward drive swi-tching than where the two mechanisms are arranged in the opposite order. Furthe.rmore, a hand lever for operating the backwar~-forward drive swi.tc~ing mechanism
3~

is generally disposed adjacent a lever for operating the main change-speed mechanism since backward-for~ard switching operations are often carried out along with main change-speed operations. The construction of the present invention in which the backward-forward drive swi-tching mechanism is disposed forwardly of the auxili.ary change-speed mechanism permits the backward-forward drive switching mechanism to be located closer to the hand lever therefor than where the backward-forward drive switching mechanism is disposed rearward]y of the auxiliary change-speed mechanism, thereby simplifying the interlocking between the backward-forward drive switching mechanism and the hand lever there~or and also simplifying the structure for its operation.
Other objects and advantages of the presen~ invention will be apparent from the following description.

Brief Description of the Dra~ings : The drawings illustrate a tra:nsmission for a tractor according to the present invention, in which;
; Fig. 1 is a side elevation of a tractorl Fig. 2 is a vertical section of the transmission, Fig. 3 is a vertical section showing a backward-forward drive switchihng mechanism and an i.nterlocking system there-for, Fig. 4 is a plan view of hand levers, Fig. 5 is a vertical section of a modified transmission, and Fig. 6 and 7 are views showing different backward-forward drive swithcing mechanism for the purpose of comparison.

Description of the Preferred Embodiment Figo 1 shows a four wheel drive tractor comprising a tractor body mounted on a propelling system A or front and rear drive wheels 1 and 2. The tractor has an engine E
at the front and a lift arm 3 and a power -takeoff shaft 4 at the rear for coupling various kinds of working implement such as a rotary cultivator and a mower to the tractor.
Power is transmitted from the engine E to -the drive wheels 1 and 2 through a main clutch 5, a main change-speed mechanism ~, a gear type backward-forward drive switching mechanism 7, an auxiliary change-speed mechanism 3 and a differential mechanism 9, and to the power takeoff shaft 4 -through the main clutch 5 and a further change-speed mechanism 10.
Thus the tractor is adap-ted to carry our varied functions by trailing and driving a working implement.
this transmission s-tructure for transmitting the power of the engine E to the front and rear wheels 1 and 2 and to the power takeoff shaft 4 is particularly described with reference to Fig. 2. The power of engine E is transrnitted to an input shaft 13 of the transmission through the maln clutch 5 disposed in a clutch housing 11~ From -the input shaft 13 the power is transmitted to a first lay shaft 15 of the propelling system through the gear type main change-speed mechanism 6 adapted to provide four speeds and disposed in a first case 14 removably attached to the clutch housing 11, and to the power takeoff shaft 4 through the gear -type change-speed mechanism 10 also disposed in the first case 14 and adapted to provide two speeds. From the first lay shaft 15 the power is giYen to the gear type backward-forward drive switching mechanism 7 housed in a spacer case 16 removably attached to the first case 14, and then to a second lay shaft 17 which is an output shaft of the backward-forward switching mechanism 7. From the second lay shaft 17 the power is given to the gear type auxiliary change-speed mecha-nism 8 housed in a second case 18 removably attached to 15 the spacer case 16, the auxiliary change-speed mechanism 8 being adapted to provide two speeds, and then to a pinion shaft 19. From the pinion shaft 19 the power is transmitted to the rear wheels 2 through the dif~erential mechanism 9 and to the front wheels through a gear type transmission mechanism 20 and a transmission shaft 21.
The first and second cases 14 and 18 and the spacer case 16 together constitute a transmission case.
The main change-speed mechanism comprises four gears 22a, 22b, 22c and 22d having different diameters from one another and fixed to the input shaft 13, and four shift gears 23a, 23b, 23c and 23d axially slidably mounted on the first lay 3~

shaft 15 which is parallel to the input shaft 13. The shift gears 23a and 23b form a pair and the shift gears 23c and 23d form another pair to be engageable with the gears 22a...., respec-tively. Two shift forks 24a and 24b 5 to shift the two pairs of shift gears 23a, respec-tively, are rigidly attached to a rod 26 slidably supported by a first casing member 25 which is removably attached to the first case 14. ~ hand lever 28 oscillatable crossways for operating the main change~speed mechanism is provided on a second casing member 27 removably attached to the first case 25, the hand lever 28 being selectively engageable with the two shift forks 24a and 24b.
Referring to Fig. 3, the backward-forward drive switching mechanism,7 comprises an inpu-t shaft, which is tne first la~ shaf t 15, supported by a partition wall 16a and carrying a first gear 29 and a second gear 30 opposed to each other across the partition wall 16a, the first gear 29 being rotatable together with the first lay shaft 15 and the second gear 30 being freely ro-tatable relative to the first lay shaft 15, the partition wall 16a being an extension of the spacer case 16. There is provided a further lay shaft 31 extending parallel to the first lay shaft 15 between the partition wall 16a and a partition member 16b opposed to the wall 16a. The lay shaft 31 carries a third gear 32 and a fourth gear 33 rotatable together with the lay shaft 31.
The third gear 32 is in mesh with the first gear 29, and the fourth gear 33 is in operative connection with the second gear 30 through a reversing gear 34, whereby the first and second gears 29 and 30 are constan-tl~v rotating in opposite ¦ directions. The first lay shaft 15 carries a ~i~th gear 35 at the rear end thereof which is rotatable with the first lay shaft 15, and the second lay shaft 17 which is in abutting relationship wi-th the first lay shaft 15 carries a two step gear 36 at the forward end thereof rotatable together with the second lay shaf-t 17. An internally threaded shift gear 37 straddles between and axially sliclably along the first and second lay shafts 15 and 17 and, together with the fifth gear 35 and the two step gear 36, constitutes a clutch mechanism 38. ~he shift gear 37 is slidable between a position to interlock the fifth gear 35 and the two step gear 36 wherehy the tractor travels forward and a position to interlock the second gear 30 and the two step gear 36 through a toothed portion 3g integral with the second gear 30 whereby the tractor travels backward.
A hand lever 40 for backward-forward drive switching operations is provided on the second casing member 27 ne~t to and on the lefthand side of the hand lever 28 for operating the main change-speed mechanism 6, the hand lever 40 being oscillatable in longitudinal directions of the tractor body.
The lever 40 engages an element 41 attachecl to a first shift rod 42 slidably mounted in the first casing member 25.
A second shift rod 43 is disposed below the rear end of 33~L

the first shift rod 42 and is slidably supported by a first and a second parti.tion walls 14a and 14b opposed to each other in the longitudinal direction of the tractor body.
The second shift rod 43 is rigidly connected at the forward end thereof to a rearward portion of the fi.rst shift rod 42 by an interlocking arm 45, and carries a fork member ~4 at the rearward end thereof to engage the shift gear 37.
The described construction facilitates the change-speed operations and the backward and forward drive switching operations when -the tractor is subjected to a frequent repeti-tion of backward and forward movements during mowing work,for example.
In the drawings, particularly in Figo 3, numeral 50 indicates a ball stopper structure provided in the second partition wall 14b to maintain the hand lever 40 for operating the backward-forward drive swi-tching mechanism 7 in a forward drive position, a neutral position or a backward drive posi-tion~
A third casing member 46 is removably attached to -the first casing member 25 rearwardly of the second casing member 27, and a hand lever ~7 is provided on the third casing member 46 oscillatably in sidewise directions on a vertical axis to effect change speed on the power takeo~f shaft ~
The hand lever 47 is operatively connected to a shift rod (not shown) supported by the first casing member 25 slidably in the longitudinal direction of the tractor body. The shift 3~

rod carries a shift fork 48 rigidly attached -thereto and operatively connected to a shift gear 49 adapted to transmit power from the input shaft 13 of the transmission -to the power takeoff shaft 4 in two alternative speeds.
Referring to Fig. 5 showing a modified transmission, the main clutch 5 comprises what is known as the double clutch type which breaks power transmission to the power takeoff shaft 4 by a first step operation and breaks power transmission to the propelling system A as well by a second step operation. Furthermore, in the backward-forward drive switching mechanism 7, the firs-t to four-th gears 29, 30, 32 and 33 and the reversing gear have such transmission ratios that the backward traveling speeds are greater than the forward traveling speeds.
As described, the spacer case 16 housing the backward-forward drive switching mechanism 7 is removably attached to the first case 14 housing the main-change speed mechanism 6 and the second case 18 housing the auxiliary change--speed mechanisM 8. This arrangement has the following advantages.
There is a case where a tractor desirably has greater backward -traveling speeds than forward traveling speeds, and there is a case opposite thereto. So the backward-forward drive switching mechanism must be provided with gears having trans-mission ratios suited to the functions of the tractor.
It has heretofore been necessary to change all of the main change-speed mechanism, the auxiliary change-speed mechanism ~ ~L9~3~

and the bac~ward forward drive switching mechanism to obtain transmissions of different designs, which has resulted in the high manufacturing costs. According to the present invention, the main change-speed mechanism 6, the first case 1~ housing the main change-speed mechanism 6, the auxiliary change-speed mechanism 8 and the second case 18 housing the auxiliary change-speed mec~anism need not be Ghanged and only the backward~forward drive switching mechanism 7 is interchangeable with its like having gears of different transmission ratios. A different transmission may be obtained simply by operatively connecting the different type of backward-forward drive switching mechanism to -the main change-speed mechanism 6 and the auxiliary change-speed mechanism 8 and by assembling ~15 the spacer case 16 to the first and second cases 1~ and 18.
The transmission may also be adjusted to tractors having different distances between the engine E and the rear wheels ! 2, by employing the spacer case 16 and the shafts of the baclcward-forward drive switching mechanism 7 having suitable lengths, thereby adjusting the wheelbase. Thus the present invention realizes a tractor transmission whose backward-forward drive switching mechanism 7 may have varied gear transmission ratios, which is on the whole simple to assemble and inexpensive to manufacture.
In the described embodiments, the interloclcing structure for operating the backward-forward drive switching mechanism 33~

is made si~ple and has compact constituent elements~ and yet is capable of smooth and reliable switching operation.
More particularly, the hand levers 28 and 40 for operating the main change-speed mechanism 6 and the gear type backward-forward drive switching mechanism 7, respectively, areprovided on the transmission case above the main change-speed mechanism 6. The first shift rod 42 engaged by the hand lever 40 for backward-forward drive switching operation is mounted slidably in the transmission case. The second shift rod 43 is disposed below and substantially parallel to the first shift rod 42 and is slidably supported by a pair of partition walls 14a and l~b opposed to each other in the transmission case. The second shift rod 43 is rigidly connected at the forward end thereof to the first shift rod 42 by the interlocking arm 45 and carries the fork member ~ 44 at the rearward end thereof to engage the gear type backward-forward drive switching mechanism 7.
Since the main change-speed mechanism 6, the gear type backward-forward drive switching mechanism 7 and the auxiliary change-speed mechanism 8 are arranged in the mentioned order in the transmission case, the backward-forward drive switching is effected under a low speed condition provided by the main change-speed mechanism and therefore more smoothly than where the gear type backward-forward drive switching mechanism 7 is disposed forwardly of the main change-speed mechanism 6. MoreoverJ since the backward-forward drive 3~

switching lever 40 as well as the mai~ change-speed ~ever 28 are provided above the main change-speed mechanism 6, the operator can change his grip to and fro between the hand levers 28 and 40 easily and quiclsly when carrying out a mowing operation or the like which requires a frequent repetition o~ the main change-speed and backward-forward switching operations.
According to the present invention, the backward-forward drive switching mechanism 7 is disposed forwardly of the auxiliary change-speed mechanism 8 as described. This arrangement has the advantage over the opposite order in that the hand lever 40 and the backward-for~ard drive switch-ing mechanism 7 are a short distance apart which helps simplify the interlocking mechanism therebetween. Moreover, the hand lever 40 and the backward-forward drive switching mechanism 7 are interlocked the first shift rod 42, the second shift rod 43 disposed therebelow and carrying the fork member 44, and the inter~ocking arm 45 extending between the two shift rods 42 and 43, in other words, the fork member 44 is interlocked with the backward-forward drive switching lever 40 provided above the main change-speed mechanism 6 through a single continuous rod. Therefore, it is un-necessary to change the construction of the transrnission case or form it in a bending shape. Besides, since the second shift rod 43 extends through the opposed partition walls 14a and 14b within the transmission case to obtain ~ 3~ ~ ~

a strong support therefrom, the second shift rod 43 may comprise a thin piece and the interlocking arm ~5 need not be very strong, wherefore these interlocking elements 42, 43 and 45 are all made simple and compact.
In the forgoing embodiments~ the gear type backward-forward drive switching mechanism is constructed to be compact by rationall~ arranging the gears. ~ore particularly9 the clutch mechanism 38 is provided between the input shaft 15 of the gear type backward-forward drive switching mechanism 7 to receive power *rom the main change-speed mechanism 6 and the output shaft 17 of the drive switching mechanism '7 to give power to the auxiliary change-speed mechanism 8, and this clutch mechanism 38 is switchable between a position to coup]e -the input shaft 15 and the output shaft 17 directly 15- and position to operatively connect the two shafts 15 and 17 through the reversing gear 38. The input shaft 15 carries the first and second gears 29 and 30 across the partition wall 16a supporting the input shaft 15, the first gear 29 being rotatable together with the input shaft 15 and the second gear 30 being rotatable relative to the input shaft 15.
The partition wall 16a further supports the lay shaft 31 to be parallel to the input shaft 15, the lay shaft 31 carry~
ing the third and fourth gears 32 and 33 across the partition wall 16a, both gears being rotatable together with the lay shaft 31. The third gear 32 is in mesh with the first gear 23 and the fourth gear 33 is in mesh with the second gear 30 through the reversing gear 34.

3~

In the above-described construction of the gear type backward-forward drive switching mechanism 7, the pair of first and second gears 29 and 30 and -the pairof third and forth gears 32 and 33 respectively mounted on the input shaft 15 and the lay shaft 31 which are necessary for revers~
ing the drive transmitting state are divided across the partition wall 16 as described. By virtue of this arrange-ment, the reaction forces act on these gears during power transmission such that the bending forces act on the input shaft 15 and -the lay shaf-t 31, respectively, in directions to cancel one another. Therefore~ the inpue shaft 15 and the lay shaft 31 may each comprise a thin piece having a relatively small strength, and the input shaft may project from the partition ~all 16a only slightly, which together contribute toward the compact construction of the gear type backward-forward drive switching mechanism 7.
For a better understanding of the advantages of the above construction, it is to be compared with the construction shown in Fig. 6, for example. The input shaft 15 here carries on a portion pro~ecting from -the partition wall 16a a first gear 29 rotatable together with the input shaft 15 and a second gear rotatable relative to -the input shaft 15, while the output shaft 17 carries a clutch member 51 axially slidably and rotatably together with the output shaft 17 and extending onto the input shaft.15. This clutch member 51 is slidable to switch between a position to mesh . .

3~

wi-th a toothed portion ~2 of the input shaft 15 to cause the tractor to drive forward and a position to mesh with a toothed portion 53 integral with the second gear 30 to cause the tractor to drive backwardO The input shaft 15 in this example must have a longer portion thereof` pro~ecting frorn the partition wall 16a than in the present invention in order to carry both the first and second gears 2g and 30 on the pro~ecting portion. Moreover, the reaction forces that act on the first to fourth gears 29, 30, 32 and 33 dur:ing power transmission all result in forces to bend the input shaft 15 and the lay shaft 31 away from each other.
To withstand the bending forces this construction therefore requires the input shaft 15 and the lay shaft 31 to be thick and strong.
Figu 7 shows another conceivable construction in which, instead of mounting the first-and second gears 29 and 30 on the input shaft 15 to reduce the length o~ the portion of the input shaft 15 projecting from the partition wall 16a, , only the first gear 29 is mounted on the input shaft 15 1 20 to be rota-table therewith and the second gear 30 is mounted on the output shaft 17 to be rotatable relative thereto.
However, the reaction forces that act on the first and second gears 29 and 30 will result in forces to bend the respective ends of the input and output shafts 15 and 17 away from the lay shaft 31. This brings about displacement bet~een the clutch member 51 and a toothed portion 54 of the input , - 16 -.. ,. .. ... . ~.. .. _ ._. . . _ .. .. ._ . _ . ... . . . .. ...

3:~.

shaft 15 which is detrimental to a smooth backward-forward drive switching. It is therefore again necessary for the input shaft 15 and the lay shaft 31 to be thick and strong.
The described embodiments of the present inventlon solve these problem in a rational manner.
Furthermore, since the main change-speed mechanism 6, the gear type backward-forward drive switching mechanism 7 and the auxiliary change-speed mechanism 8 are arranged in the mentioned order in the transmission case, the backward-forward drive switching is effected smoothy under a lowspeed condition provided by the main change-speed mechanism.
By providing the backward-forward drive switching mechanism 7 closer to the main change-speed mechanism 6 than is the auxiliary change-speed mechanism 8 9 the backward--forward drive switching rnechanism 7 is now disposed closer to the backward-forward drive switching lever 40 which is generally located near the operating device for the main change-speed mechanism 6 since -the backward-forward drive switching is often carried out together with the main change-speed opera-tion. The shortened distance between the backward-forward drive switching mechanism 7 and the hand lever 40 therefor has the advantage of simplifying the interlocking mechanism therebetween.

, ~ . . .

Claims (2)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLU-SIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A transmission for a tractor comprising: a main change speed mechanism for providing multiple speeds;
a gear type backward-forward drive switching mechanism for switching the multiple speeds between backward and forward rotations; an auxiliary change speed mechanism; a trans-mission case including a first case housing said main change speed mechanism, a second case housing said auxiliary change speed mechanism, and a spacer case removably attached to said first and second cases and housing said gear type backward-forward drive switching mechanism, said first ease being disposed forwardly of said second case with said spacer case in between said first case and said second case;
change speed and drive switching levers provided on said transmission case for operating said main change speed mech-anism and said gear type backward-forward drive switching mechanism respectively, and rigid interlocking means housed in said transmission case and operatively connecting in a push-pull manner said drive switching lever to said drive switching mechanism; said interlocking means including a first shift rod connected to said drive switching lever, a second shift rod disposed substantially parallel to and downwardly of said first shift rod to an end of said second shift rod opposed to said drive switching lever, and a fork member attached to the other end of said second shift rod for actuating said drive switching mechanism; said second shift rod extending through an opposed parallel pair of partition walls provided in said transmission case, said second shift rod being guided and supported by at least one opening defined in one of said partition walls.
2. A transmission as claimed in claim 1 wherein said gear type backward-forward drive switching mechanism comprises an input shaft for transmitting power from said main change-speed mechanism to said gear type backward-forward drive switching mechanism, an output shaft for transmitting power from said year type backward-forward drive switching mechanism to said auxiliary change-speed mechanism, a clutch mechanism adapted to switch between a position to place said input shaft and said output shaft in direct connection and a position to place said input shaft and said output shaft in operative connection via a reversing gear, said input shaft, carrying for operative connection with said reversing gear a first gear and a second gear disposed across a partition wall supporting said in-put shaft, said first gear being fixed to said input shaft, said second gear being freely rotatable on said input shaft, and a transmission shaft supported parallel to said input shaft by said partition wall, said transmission shaft carrying a third gear and a fourth gear disposed across said partition wall and rotatable in unison with each other, said third gear being in mesh with said first gear, said fourth gear being in mesh with second gear through said reversing gear.
CA000389031A 1980-12-05 1981-10-29 Tractor transmission Expired CA1190831A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP175081/1980 1980-12-05
JP17508180U JPS5797727U (en) 1980-12-05 1980-12-05

Publications (1)

Publication Number Publication Date
CA1190831A true CA1190831A (en) 1985-07-23

Family

ID=15989900

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000389031A Expired CA1190831A (en) 1980-12-05 1981-10-29 Tractor transmission

Country Status (5)

Country Link
JP (1) JPS5797727U (en)
CA (1) CA1190831A (en)
DE (1) DE3143819A1 (en)
FR (1) FR2495550B1 (en)
GB (1) GB2088974B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59196325U (en) * 1983-06-15 1984-12-27 株式会社クボタ Vehicle gear shift operation device
JPS6127779A (en) * 1984-07-17 1986-02-07 ヤマハ発動機株式会社 Car for travelling on uneven ground
DE19837776A1 (en) * 1998-08-20 2000-02-24 Zahnradfabrik Friedrichshafen Gearbox of motor driven vehicle, comprising of several shafts and notched wheels, is reduced in size by specific arrangement of same

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT276109B (en) * 1967-03-16 1969-11-10 Steyr Daimler Puch Ag Switching device for gear change transmissions of farm tractors
DE2065300C3 (en) * 1970-10-07 1979-04-26 Kloeckner-Humboldt-Deutz Ag, 5000 Koeln Switching device for a gear change transmission for vehicles, preferably of a group design
DE2220729A1 (en) * 1972-04-27 1973-11-08 Fendt & Co Xaver GEAR ARRANGEMENT FOR OFF-ROAD MOTOR VEHICLES, IN PARTICULAR AGRICULTURAL VEHICLES
JPS5523989B2 (en) * 1974-04-22 1980-06-26
BR7603032A (en) * 1975-05-14 1977-05-31 Massey Ferguson Services Nv IMPROVEMENT IN SPEED CHANGE TRANSMISSION
DE2645907C3 (en) * 1976-10-12 1982-04-08 Xaver Fendt & Co, 8952 Marktoberdorf Gear change transmission
JPS5430732U (en) * 1977-08-03 1979-02-28
JPS5447230A (en) * 1977-09-20 1979-04-13 Kubota Ltd Double clutch device for agricultural tractor
GB2013595B (en) * 1978-01-31 1982-09-08 Kubota Ltd Power transmission system for a tractor

Also Published As

Publication number Publication date
GB2088974A (en) 1982-06-16
FR2495550B1 (en) 1989-02-10
DE3143819A1 (en) 1982-07-15
GB2088974B (en) 1985-05-22
FR2495550A1 (en) 1982-06-11
JPS5797727U (en) 1982-06-16

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