GB2088974A - Traction transmission - Google Patents

Traction transmission Download PDF

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Publication number
GB2088974A
GB2088974A GB8133588A GB8133588A GB2088974A GB 2088974 A GB2088974 A GB 2088974A GB 8133588 A GB8133588 A GB 8133588A GB 8133588 A GB8133588 A GB 8133588A GB 2088974 A GB2088974 A GB 2088974A
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GB
United Kingdom
Prior art keywords
gear
drive switching
transmission
switching mechanism
backward
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.)
Granted
Application number
GB8133588A
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GB2088974B (en
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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
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Publication of GB2088974A publication Critical patent/GB2088974A/en
Application granted granted Critical
Publication of GB2088974B publication Critical patent/GB2088974B/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
    • F16H63/02—Final output mechanisms therefor; Actuating means for the final output mechanisms
    • F16H63/24—Final 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT 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
    • B60K17/00—Arrangement or mounting of transmissions in vehicles
    • B60K17/04—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing
    • B60K17/06—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of change-speed gearing
    • B60K17/08—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of change-speed gearing of mechanical type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
    • F16H3/08—Toothed 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
    • F16H3/14—Gearings for reversal only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/04—Combinations of toothed gearings only
    • F16H37/042—Combinations of toothed gearings only change gear transmissions in group arrangement
    • F16H37/043—Combinations of toothed gearings only change gear transmissions in group arrangement without gears having orbital motion

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  • 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

A transmission for a tractor comprising a main change-speed mechanism (6), an auxiliary change-speed mechanism (8), and a gear type backward-forward drive switching mechanism (7) for transmitting power from an engine to a propelling system, such as front and rear drive wheels. The main change-speed mechanism (6), the gear type backward-forward drive switching mechanism (7), and the auxilary change-speed mechanism (8) are arranged in a transmission case (14, 16, 18) in the aforementioned order in the forward to rearward direction of the tractor. A power take-off shaft 4 is driven through a further change-speed mechanism 10. <IMAGE>

Description

SPECIFICATION Tractor transmission 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 transmitting power from an engine to a propelling system.
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 three fashions, namely combined into the main change-speed mechanism, disposed forwardly of the main change-speed mechanism, or disposed rearwardly of the auxiliary change-speed mechanism.
The case where the gear type backwardforward drive switching mechanism is combined into the main change-speed mechansim is merely a remnant of the times when plural backward speeds were unnecessary for tractors, as they still are for ordinary motor vehicies. Such a construction cannot meet the requirement of tractors to perform varied functions by utilizing plural backward speeds.
In order to meet this requirement, plural backward speeds are now provided. A backwardforward drive switching mechanism to provide plural backward speeds without necessitating extensive modifications to the main change-speed mechanism is in many instances disposed forwardly of the main change-speed mechanism so as to reverse the rotation of a transmission shaft prior to the power input to the main changespeed mechanism. However, this arrangement involves a change gear operation prior to reduction of the engine speed by the main change-speed mechanism, and therefore has the disadvantage of having to effect gear meshing under high speed rotation, 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 changespeed mechanism adjacent the driver's seat. This arrangement has the disadvantage of requiring a long interlocking mechanism operatively connecting the backward-forward drive switching mechanism to its hand lever.
The object of this invention is substantially to overcome the drawbacks of the prior art constructions described above and to arrange the gear type backward-forward drive switching mechanism in a rational manner which is operable by a simple interlocking mechanism and effects a smooth backward-forward drive switching.
According to the present invention, a transmission for a tractor comprises a main change-speed mechanism, an auxiliary changespeed mechanism, and a gear type backwardforward drive switching mechanism for transmitting power from an engine to a propelling system, wherein the main change-speed mechanism, the gear type backward-forward drive switching mechanism, and the auxiliary changespeed mechanism are arranged in a transmission case in the aforementioned order in the forward to rearward direction of the tractor.
More particularly, the construction according to the present invention in which the main changespeed mechanism, the gear type backwardforward drive switching mechanism, and the auxiliary change-speed mechanism are arranged in a transmission case in the aforementioned 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 switching than where the two mechanisms are arranged in the opposite order.Furthermore, a hand lever for operating the backward-forward drive switching mechanism is generally disposed adjacent a lever for operating the main changespeed mechanism since backward-forward switching operations are often carriers out along the main change-speed operations.
The construction of the present invention in which the backward-forward drive switching mechanism is disposed forwardly of the auxiliary change-speed mechanism permits the backwardforward drive switching mechanism to be located closer to the operating hand lever therefor than where the backward-forward drive switching mechanism is disposed rearwardly of the auxiliary change-speed mechanism, thereby simplifying the interlocking between the backward-forward drive switching mechanism and the operating hand lever therefor and also simplifying the structure for its operation.
The invention will now be further described, by way of example, with reference to the accompanying drawings which iliustrate embodiments of tractor transmission according to the present invention and in which; Fig. 1 is a side elevation of a tractor, Fig. 2 is a vertical section of one embodiment of tractor transmission, Fig. 3 is a vertical section showing one embodiment of a backward-forward drive switching mechanism and an interlocking system therefor, Fig. 4 is a plan view of the hand levers, Fig. 5 is a vertical section of a modified embodiment of tractor transmission, and Fig. 6 and 7 are views showing different backward-forward drive switching mechanism for the purpose of comparison.
Fig. 1 shows a four wheel drive tractor comprising a tractor body mounted on a propelling system A comprising 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 rotas cultivator and a mower to the tractor.
As shown in Fig. 2, power is transmitted from the engine E to the drive wheels 1 and 2 through a rnain clutch 5, a main change-speed mechanism 6, a gear type backward-forward drive switching mechanism 7, and auxiliary change-speed mechansim 8 and a differential mechanism 9, and to the power takeoff shaft 4 through the main clutch 5 and further change-speed mechanism 10.
Thus the tractor is adapted to carry out varied functions by trailing and driving a working implement This transmission structure for transmitting the power of the engine E to the front and rear wheels 1 and 2 and to the power takeoff shaft 4 will now be particularly described with reference to Fig. 2.
The power of engine E is transmitted to an input shaft 1 3 of the transmission through the main clutch 5 disposed in a clutch housing 11. From the input shaft 1 3 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 1 1; and power is also transmitted 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 1 5 the power is applied to the gear type backward-forward drive switching mechanism 7 housed in a spacer case 1 6 removably attached to the first case 14, and then to a second lay shaft 1 7 which is an output shaft of the backward-forward switching mechanism 7.
From the second lay shaft 17 the power is applied to the gear type auxiliary change-speed mechanism 8 housed in a second case 1 8 removably attached to the spacer case 16, the auxiliary change-speed mechanism 8 being adapted to provide two speeds, and then to a pinion shaft 1 9. From the pinion shaft 19 the power is transmitted to the rear wheels 2 through the differential 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 1 8 and the spacer case 1 6 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 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, 22b, 22c and 22d, respectively. Two shift forks 24a and 24b to shift the two pairs of shift gears 23a, 23b respectively, are rigidly attached to a rod 26 slidably supported by a casing member 25 which is removably attached to the first case 14. A hand lever 28 oscillatable crossways for operating the main change-speed mechanism is provided on a casing member 27 removably attached to the casing member 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 input shaft, which is the first lay shaft 15, supported by a partition wall 1 6a and carrying a first gear 29 and a second gear 30 on opposite sides of the partition wall 16a, the first gear 29 being rotatable together with the first lay shaft 1 5 and the second gear 30 being freely rotatable relative to the first lay shaft 15, the partition wall 1 6a being an extension of the spacer case 1 6. There is also provided a further lay shaft 31 extending parallel to the first lay shaft 1 5 between the partition wall 1 6a and a partition member 1 6b opposite 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 constantly rotating in opposite directions. The first lay shaft 1 5 carries a fifth 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 with the first lay shaft 1 5 carries a two step gear 36 at the forward end thereof rotatable together with the second lay shaft 1 7.
An internally threaded shift gear 37 straddles between and is axially slidably along the first and second lay shafts 1 5 and 1 7 and, together with the fifth gear 35 and the two step gear 36, constitutes a clutch mechanism 38. The shift gear 37 is slidable between a position to interlock the fifth gear 35 and the\two step gear 36 whereby the tractor travels forward and a position'to interlock the second gear 30 and the two step gear 36 through a toothed portion 39 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 casing member 27 next to and on the left-hand side of the hand lever 28 for operating the main changespeed mechanism 6, the hand lever 40 being oscillatable in longitudinal directions of the tractor body. The lever 40 engages an element 41 attached to a first shift rod 42 slidably mounted in the casing member 25. A second shift rod 43 is disposed below the rear end of the first shift rod 42 and is slidably supported by first and second partition walls 1 4a and 1 4b opposite 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 first shift rod 42 by an interlocking arm 45, and carries a fork member 44 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 repetition of backward and forward movements, for example during mowing work.
In the drawings, particularly in Fig. 3, numeral 50 indicates a ball stopper structure provided in the second partition wall 1 4b to maintain the hand lever 40 for operating the backward-forward drive switching mechanism 7 in a forward drive position, a neutral position or a backward drive position.
A casing member 46 is removably attached to the casing member 25 rearwardly of the casing member 27, and a hand lever 47 is provided on the casing member 46 oscillatably in sidewise directions on a vertical axis to effect change speed on the power takeoff shaft 4. The hand lever 47 is operatively connected to a shift rod (not shown) supported by the casing member 25 slidably in the longitudinal direction of the tractor body. The shift rod carriers 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 at two alternative speeds.
Referring to Fig. 5 which shows a modified transmission, the main clutch 5 is what is known as of 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 first to fourth gears 29, 30, 32 and 33 and the reversing gear have such transmission ratios that the backward travelling speeds are greater than the forward travelling speeds.
As described, the spacer case 1 6 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 1 8 housing the auxiliary changespeed mechanism 8. This arrangement has the following advantages. There are cases where a tractor desirably has greater backward travelling speeds than forward travelling speeds, and there are cases opposite thereto. So the backwardforward drive switching mechanism must be provided with gears having transmission ratios suited to the functions of the tractor.It has therefore been necessary to change all of the main change-speed mechanism, the auxiliary changespeed mechanism and the backward-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 14 housing the main change-speed mechanism 6, the auxiliary change speed mechanism 8 and the second case 1 8 housing the auxiliary change-speed mechanism 8 need not be changed and only the backwardforward drive switching mechanism 7 is interchangeable with a similar one 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 the spacer case 1 6 to the first and second cases 14 and 1 8. The transmission may also be adapted to suit tractors having different distances between the engine E and the rear wheels 2, by employing spacer case 1 6 and shafts of the backward-forward drive switching mechanism 7 having suitable lengths, thereby adjusting the wheelbase. Thus the present invention provides 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 interlocking structure for operating the backward-forward drive switching mechanism is made simple 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 mechanism 7, respectively, are provided on the transmission case above the main changespeed mechanism 6. The first shift rod 42 engaged by the hand lever 40 for backwardforward 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 1 4a and 1 4b 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. Moreover, since the backward-forward drive switching lever 40 as well as the main change-speed lever 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 quickly when carrying out a mowing operation or the like which requires a frequent repetition of 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-forward drive switching 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, since the first shift rod 42, the second shift rod 43 disposed therebelow and carrying the fork member 44, and the interlocking 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 unnecessary to change the construction of the transmission case or form it in a bending shape.Besides, since the second shift rod 43 extends through the opposed partition walls 1 4a and 1 4b within the trniismission case to obtain a strong support therefrom, the second shift rod 43 may comprise a thin piece and the interlocking arm 45 need not be very strong, wherefore these interlocking elements 42, 43 and 45 are all made simple and compact.
In the foregoing embodiments, the gear type backward-forward drive switching mechanism is constructed so as to be compact by rationally arranging the gears. More particularly, the clutch mechanism 38 is provided between the input shaft 1 5 of the gear type backward-forward drive switching mechanism 7 to receive power from 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 couple the input shaft 1 5 and the output shaft 1 7 directly and a position to operatively connect the two shafts 1 5 and 1 7 through the reversing gear of clutch 38.
The input shaft 1 5 carriers 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 1 5 and the second gear 30 being rotatable relative to the input shaft 1 5. The partition wall 16a further supports the lay shaft 31 to be parallel to the input shaft 15, the lay shaft 31 carrying 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 29 and the fourth gear 33 is in mesh with the second gear 30 through the reversing gear 34.
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 pair of third and fourth gears 32 and 33 respectively mounted on the input shaft 1 and the lay shaft 31 which are necessary for reversing the drive transmitting state are divided across the partition wall 1 6 as described. By virtue of this arrangement, the reaction forces act on these gears during power transmission such that the bending forces act on the input shaft 1 5 and the lay shaft 31 respectively in directions to cancel one another.Therefore, the input shaft 1 5 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 wall 1 6a only slightly, which together contribute towards the compact construction of the gear type backwardforward 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 1 5 here carries on a portion projecting from the partion wall 1 6a a first gear 29 rotatable together with the input shaft 1 5 and a second gear rotatable relative to the input shaft 1 5, while the output shaft 1 7 carries a clutch member 51 axially slidably and rotatably together with the output shaft 1 7 and extending onto the input shaft 1 5. This clutch member 51 is slidable to switch between a position to mesh with a toothed portion 52 of the input shaft 1 5 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 backward. The input shaft 15 in this example must have a longer portion thereof projecting from the partition wall 1 6a than in the present invention in order to carry both the first and second gears 29 and 30 on the projecting portion.Moroever, the reaction forces that act on the first to fourth gears 29, 30, 32 and 33 during 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.
Fig. 7 shows another conceivable construction in which, instead of mounting the first and second gears 29 and 30 on the input shaft 1 5 to reduce the length of the portion of the input shaft 1 5 projecting from the partition wall 16a, only the first gear 29 is mounted on the input shaft 1 5 to be rotatable 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 between the clutch member 51 and a toothed portion 54 of the input shaft 1 5 which is detrimental to a smooth backward-forward drive switching.It is therefore again necessary for the input shaft 1 5 and the lay shaft 31 to be thick and strong. The described embodiments of the present invention solve these problems 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 smoothly under a low speed 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, the backward-forward drive switching mechanism 7 is now disposed closer to the backward-forward drive switching lever 40 which is generally located near the operating device for the main changespeed mechanism 6 since the backward-forward drive switching is often carried out together with the main change-speed operation. 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 (6)

1. A transmission for a tractor comprising a main change-speed mechanism, an auxiliary change-speed mechanism, and a gear type backward-forward drive switching mechanism for transmitting power from an engine to a propelling system, wherein said main change-speed mechanism, said gear type backward-forward drive switching mechanism, and said auxiliary change-speed mechanism are arranged in a transmission case in the aforementioned order in the forward to rearward direction of the tractor.
2. A transmission as claimed in claim 1, further comprising a first case housing said main changespeed 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 backwardforward drive switching mechanism.
3. A transmission as claimed in claim 1 or 2, further comprising a first hand lever for operating said main change-speed mechanism, a second hand lever for operating said gear type backwardforward drive switching mechanism, both said hand levers being provided on said transmission case, a first shift rod slidable by movement of said second hand lever for operating said gear type backward-forward drive switching mechanism, a second shift rod disposed below and substantially parallel to said first shift rod and extending through and slidably supported by an opposed parallel pair of partition walls provided in said transmission case, an interlocking arm rigidly connecting one end of said second shift rod to said first shift rod, and a fork member attached to the other end of said second shift rod for actuating said gear type backward-forward drive switching mechanism.
4. A transmission as claimed in any one of claims 1 to 3, wherein said gear type backwardforward 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 gear type backward-forward drive switching mechanism to said auxiliary change-speed mechanism, a clutch mechanism adapted to switch between a first position to place said input shaft and said output shaft in direct connection and a second 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 input shaft, said first gear being fixed to said input shaft and 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, and said fourth gear being in mesh with second gear through said reversing gear.
5. A transmission for a tractor substantially as hereinbefore described with reference to Figs. 1 to 4, or Figs. 1, 3, 4 and 5 of the accompanying drawings.
6. A tractor incorporating a transmission as claimed in any preceding claim.
GB8133588A 1980-12-05 1981-11-06 Tractor transmission Expired GB2088974B (en)

Applications Claiming Priority (1)

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

Publications (2)

Publication Number Publication Date
GB2088974A true GB2088974A (en) 1982-06-16
GB2088974B GB2088974B (en) 1985-05-22

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8133588A Expired GB2088974B (en) 1980-12-05 1981-11-06 Tractor transmission

Country Status (5)

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

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4738326A (en) * 1984-07-17 1988-04-19 Yamaha Hatsudoki Kabushiki Kaisha Off the road vehicle
US6612960B1 (en) 1998-08-20 2003-09-02 Zf Friedrichshafen Ag Transmission with non-coaxial output

Families Citing this family (1)

* 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

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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

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4738326A (en) * 1984-07-17 1988-04-19 Yamaha Hatsudoki Kabushiki Kaisha Off the road vehicle
US6612960B1 (en) 1998-08-20 2003-09-02 Zf Friedrichshafen Ag Transmission with non-coaxial output

Also Published As

Publication number Publication date
FR2495550B1 (en) 1989-02-10
GB2088974B (en) 1985-05-22
FR2495550A1 (en) 1982-06-11
JPS5797727U (en) 1982-06-16
CA1190831A (en) 1985-07-23
DE3143819A1 (en) 1982-07-15

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