JPS62167959A - Transmission for tractor - Google Patents

Abstract

PURPOSE:To attain a larger number of vehicle speeds in an original necessary vehicle speed range, by providing a secondary speed changer and a creep speed changer at the output side of a primary speed changer. CONSTITUTION:A secondary speed changer 28 having a speed changing sections for a high, a medium and a low speeds, and a creep speed changer 71 having a creep speed changing section, which can be optionally connected to or disconnected from only the low speed changing section of the secondary speed changer and serves to attain a creep speed lower than that by the low speed changing section, are provided at the output side of a primary speed changer 16 for altering the speed of a rotation from an engine 1. As a result, a high, a medium and a low vehicle speeds appropriate to different kinds of work can be attained, a vehicle speed, which is attained by an auxiliary speed changer and cannot be easily discerned, is eliminated, and a larger number of vehicle speeds are attained in an original necessary vehicle speed range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission for a tractor, and an object of the present invention is to provide a transmission for a tractor with a simple structure that can evenly obtain the necessary vehicle speed and obtain an ideal vehicle speed.

Tractors, which are frequently used for agricultural and civil engineering construction purposes, must have vehicle speeds that are suitable for various types of work such as trencher work, snow removal work, row plowing/frame work, plow work, and trailer towing work.

Therefore, as a transmission for a tractor, a secondary transmission, that is, an auxiliary transmission, which can perform two-stage high-low gear shifting, is provided on the output side of a primary transmission that shifts the rotational power of the engine into multiple stages. A creep (super deceleration) device is installed.

However, in a transmission with such a configuration, the creep device is installed as a so-called auxiliary transmission of the auxiliary transmission, and although it is possible to obtain a large amount of vehicle speed, the vehicle speed may increase unnecessarily and cause confusion. The vehicle speed is correct.

In other words, the driver was unable to vary the vehicle speed precisely within the originally required vehicle speed range, and was instead using a vehicle speed that was rarely used.

The present invention was devised in view of the actual situation, and includes a high-speed transmission section and an intermediate transmission section that is slower than the high-speed transmission section on the output side of a primary transmission that shifts the rotational power of the engine into multiple stages. A secondary transmission is provided, each having a high-speed transmission and a low-speed transmission, each having a lower speed than the medium-speed transmission. It transmits high speed, medium speed and low speed power from the medium speed transmission section and the low speed transmission section to the differential mechanism, and is in and out of contact only with respect to the low speed transmission section of the secondary transmission device. The present invention is characterized in that a creep transmission device having a creep transmission section having a lower speed than a low speed transmission section is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows the overall structure of a tractor transmission, and FIG. 2 shows the main parts of the present invention.

First, in FIG. 1, 1 is an engine and 2 is a running clutch. Reference numeral 3 denotes a propulsion shaft for traveling, which has a cylindrical shaft structure and is connected or disconnected by the engagement or disengagement of the clutch 2.

Reference numeral 4 denotes a PTO propulsion shaft, which is connected to the engine 1 and inserted into the traveling propulsion shaft 3 so as to be relatively rotatable.
At the rear of the propulsion shaft 4 is a hydraulic wet disc type PTO.
The clutch 5 is engaged and connected to a PTO transmission (not shown) through engagement/disengagement of the clutch 5, engagement/disengagement of the shift gear 6, etc., and drives a PTO shaft at the rear of the vehicle body.

The traveling propulsion shaft 3 has a drive gear 7, which is constantly engaged with a gear 9 on a deceleration subshaft 8 mounted parallel to the propulsion shaft 3 below.

Reference numeral 10 denotes a primary transmission shaft having a cylindrical shaft structure, which is rotatably mounted on the same axis behind the traveling propulsion shaft 3, and a one-way clutch 1 is attached to the front end of the secondary transmission shaft 10.
An interlocking gear 12 is provided via 1, and the interlocking gear 12 is always in mesh with another gear 13 on the reduction countershaft 8.

In addition, the one-way clutch 11 is connected to the gear 12 rather than the gear 13.
The rotational power of the engine is transmitted only towards the

Reference numeral 14 denotes a propulsion shaft clutch, which is a hydraulic clutch provided between the traveling propulsion shaft 3 and the primary transmission shaft 10, and has a one-way clutch 15 for starting traction. It is transmitted only toward the traveling propulsion shaft 3.

Therefore, when the propulsion shaft clutch 14 is engaged, the propulsion shaft 3 and the primary transmission shaft 10 are directly connected, and when the clutch 14 is disengaged, the power is transmitted via the deceleration subshaft 8 to the primary transmission shaft 10 via the one-way clutch 11. It is possible.

Note that the one-way clutch can be replaced by the propulsion shaft clutch 14 as a double clutch provided in a back-to-back configuration.

Reference numeral 16 denotes a primary transmission, and in this example, four transmission gears 17, 18, 19, and 20 of different diameters are fixed on the secondary transmission shaft 10 at intervals in the axial direction; Below, a transmission subshaft 21 is mounted parallel to the rear axis of the deceleration subshaft 8, and the transmission gears 17.1B, 19.20 are provided on the subshaft 21 so as to be relatively rotatable. Transmission gears 22, 23, 24 that are always engaged and interlocked with each other.
．． 25, a shifter 26 for alternatively fixing the transmission gears 22 and 23 to the transmission subshaft 21, and a shifter 27 for alternatively fixing the transmission gears 24 and 25 to the transmission subshaft 21, and the like. In this embodiment, a primary transmission 16 of a constant engagement type capable of four-speed shifting is constructed, and interlocks a subshaft 21 which is an output shaft.

Reference numeral 28 denotes a secondary transmission, which is provided on the output side of the primary transmission 16, and includes a high-speed transmission section H1, a medium-speed transmission section M having a lower speed than the high-speed transmission section H, and a medium-speed transmission section M. Each has a low-speed transmission section that is slower than the other.

That is, the high-speed transmission section H is configured by connecting and disconnecting the output shaft 21 of the primary transmission 16 and the transmission shaft 42 of the secondary transmission 28 provided on the axial extension of the output shaft 21 using the shifter 52. It is configured.

Further, the medium speed transmission section M includes the output shaft 2 of the primary transmission 16.
1 through gears 32 and 39 and is interlocked therewith, and further decelerated and interlocked with the transmission shaft 42 of the secondary transmission 28 through gear 41.47A. There is.

Furthermore, the low speed transmission section includes a gear 4 in the deceleration detour transmission path.
7B and 62, and another deceleration detour transmission path that is decelerated and interlocked with the speed change shaft 42 of the secondary transmission 28 through gears 66 and 45.

Referring also to FIG. 2, a drive gear 32 is fitted and fixed to the rear end of the sub-shift subshaft 21, and an engaging portion 33 is formed on the outer periphery of the rear end of the drive gear 32.

Reference numeral 34 denotes a secondary transmission subshaft having a cylindrical shaft structure, the front end of which is connected to the rear end of the primary transmission shaft 10 through a bearing 35, and the rear end is connected to a bearing case 37 provided in an intermediate case 36 with a bearing 38. The axial center of the secondary speed change subshaft 34 and the axis of the primary speed change shaft 10 coincide with each other.

In this example, three transmission gears 39, 40, and 41 of different diameters are fitted and fixed on the secondary transmission subshaft 34, and the large gear 39 at the front end thereof meshes with the drive gear 32.

Reference numeral 42 designates a secondary speed change shaft, which is located on the axial extension line of the secondary speed change subshaft 21, with its front end connected to the rear of the primary speed change subshaft 21 via a needle bearing 43, and its rear end connected to the rear of the primary speed change subshaft 21 via a bearing 44. It is supported by the intermediate case 36 so as to be relatively rotatable.

On the secondary transmission shaft 42 are transmission gears 45, 46, 47 of different diameters.
In this example, three gears are fitted and supported so as to be relatively rotatable at intervals in the axial direction, and the transmission gear 47 is a two-stage gear, and the large gear (47A) is the intermediate diameter of the secondary transmission subshaft 34. gear 4
It is interlocking with 1. Further, the speed change gear 46 is for reverse rotation and is connected to the secondary speed change subshaft 3 via an idle gear 48 shown in FIG.
A coupling body 49 is fixed on the secondary transmission shaft 42 between the transmission gear 46 and the transmission gear 47, and a shifter 50 on the coupling body 49 is fixed in the circumferential direction and By sliding in the direction, it can be freely engaged with and disengaged from the engaging portions (46A) and (47C) formed on the gears 46 and 47, respectively.

Further, a coupling body 51 is fitted and fixed to the front end of the secondary transmission shaft 42, and a shifter 52 is provided on the coupling body 51 so as to be fixed in the circumferential direction and slidable in the axial direction. The formed occlusion part (45A) and the occlusion part 3 of the drive gear 32
It can be freely engaged and disengaged as an alternative to 3.

Reference numerals 55 and 56 indicate low-speed transmission shafts, which have a cylindrical structure and are rotatably supported via bearings 57 and 58 in the front and rear portions of the intermediate case, respectively. Needle bearing 60.6
It is said that it is relatively rotatable via 1.

The transmission shafts 55, 56 are mounted parallel to each other below the secondary transmission shaft 42, and a gear 64, which includes large and small gears 62, 63, is fitted and fixed on the transmission shaft 55 at the rear. The large gear 62 of the gear 64 is the two-speed gear 4 of the secondary gear shaft 42.
7, and an engaging portion 65 is formed on the transmission shaft 55 at the front portion of the small gear 63.

Further, on the front transmission shaft 56, a gear 66 that engages and interlocks with the maximum diameter transmission gear 45 of the secondary transmission shaft 42 is carved at the front end in this example, and a needle is provided at the rear of the gear 66. An interlocking gear 68 for creep is fitted on the sleeve so as to be relatively rotatable via a bearing 67, and an engaging portion 69 is formed in the shape of an internal gear at the rear end side of the interlocking gear 68. Furthermore, a shifter 70 is slidably fitted on the rear end side of the front power transmission shaft 56 with a spline or the like.
5 and the interlocking portion 69 of the interlocking gear 68.

Reference numeral 71 denotes a creep device, which includes a creep transmission section 72 that is located only in the middle of the deceleration detour transmission path in the low speed transmission section and is further decelerated and interlocked with the transmission shaft 42 of the secondary transmission 28. ing.

That is, it includes a gear 73 that interlocks with the small gear 63 on the rear transmission shaft 55, and a gear 74 that interlocks with the interlocking gear 6 on the front transmission shaft 56.

In this embodiment, a removable lid 75 that covers the bottom opening of the intermediate case 36 is integrally provided with an upwardly projecting bearing arm 76, and a shaft 77 is connected to the bearing arm 76 via a bearing 77.
8 is provided relatively rotatably, and the gears 73 and 74 are respectively fixed to the front and rear ends of the shaft 78 to form a cassette structure.

In addition, in FIG. 1, reference numeral 29 denotes a differential gear, and a secondary transmission shaft 42, which is the output side of the secondary transmission 28, is interlocked via a differential drive shaft 30. A resistor 31 for inertia braking and a front wheel drive gear 79 are fixedly installed. Note that the pair of differential output shafts 80 are each linked to a rear vehicle transport 82 via a final reduction gear 81.

Reference numeral 83 denotes a first transmission shaft for driving the front wheels, which is mounted parallel to the shaft below the differential drive shaft 30, and is connected to a gear 84 which is interlocked with the drive gear 79.
has.

85 is a front wheel drive clutch, which is a hydraulic type provided between the first transmission shaft 83 and the second transmission shaft 59;
It is located on the 5th side of the clutch clutch.

The second transmission shaft 59 extends forward, and has a gear 86 fixedly attached to its front end, and a gear 87 that meshes with the gear 86 is provided on the front wheel propulsion shaft 88 .

In addition, the primary transmission i! 16 is attached to the first transmission case 89,
The secondary transmission device 28 is built into the intermediate case 36, and the differential device 29 is built into the second transmission case 90, and the abutting portions of each case 89, 36, and 90 are removably connected in a vertical plane with bolts, etc. It becomes the structure of the tractor body.

Next, the operation of the above configuration will be explained.

- In this example, by selectively engaging the shifters 26, 27 of the secondary transmission W16 with the transmission gears 22, 23, 24, 25, respectively, the rotational power of the engine 1 is shifted to four stages by the L-order transmission 16. and the transmission subshaft 21 is transmitted.

Therefore, the shifter 52, which constitutes a part of the high-speed transmission part H of the secondary transmission 28, is slid to the left in FIG. By directly connecting, the differential device 29 is interlocked via the differential drive shaft 30.

That is, in the high-speed system H of the secondary transmission 28, the vehicle speed as shown in the vehicle speed explanatory diagram of FIG. 42 is obtained.

Next, the shifter 50, which constitutes a part of the medium speed transmission section M of the secondary transmission 28, is slid to the right in FIG. When engaged with (47C), - secondary transmission subshaft 21 - drive gear 32 - large gear 39 on secondary transmission subshaft 34 - intermediate gear 41 on the same shaft 34 →
Gear 47 on secondary transmission shaft 42 - shifter 50 - combination 49
The secondary transmission shaft 42 is interlocked at medium speed through the differential drive shaft 3.
The differential device 29 is driven via the 0.

That is, in the medium speed transmission section M of the secondary transmission 28, the fourth
A clear vehicle speed can be obtained from the vehicle speed explanatory diagram in FIG.

Next, when the shifter 50 is slid to the left in FIG. 2 and engaged with the engagement portion (46A) of the reverse speed change gear 46, - secondary speed change subshaft 21 - drive gear 32 - secondary speed change subshaft 34 Upper large gear 39 - Small diameter gear 40 on coaxial 34 → Idle gear 4
8-speed gear 46-shifter 50-combined body 49, it is possible to obtain a reverse speed as shown in the vehicle speed explanatory diagram of FIG.

Next, the shifter 70 for creep is slid to the right in FIG. It engages with the engagement portion (45A) of the large speed gear 45 on the secondary speed change shaft 42. Then, the transmission subshaft 21 - the drive gear 32 - the large gear 39 on the secondary transmission subshaft 34 - the intermediate diameter gear 41 on the same shaft 34 - the transmission gear 47 on the secondary transmission shaft 42 -
Gear 64 on the rear transmission shaft 55 - shifter 70 - front transmission shaft 56 - gear 66 on the same shaft 56 - large speed gear 45 on the secondary transmission shaft 42 - shifter 52 - low speed system via the coupling body 51 The vehicle speed is obtained as shown in FIG. 4.

Next, the shifter 70 for creep is slid to the left in FIG. When the creep gear 73 engages with the engagement portion (45A) of the transmission gear 45, the creep gear 73 engages with the gear 64 on the rear transmission shaft 55 in the low-speed system described above, and the other creep gear 74 engages with the creep interlocking gear 68. Therefore, shifter 70 - front transmission shaft 56 → gear 6 low gear 45
→The creep speed from the low speed transmission part of the secondary transmission 28 which passes through the shifter 52-coupling body 51 and the creep device 71 drives the differential device 29 at the vehicle speed as shown in FIG. That's what I do.

That is, in the conventional example, as shown in FIG. 4, a secondary transmission with two high and low stages is provided in the primary transmission, and a tertiary transmission is further provided which is involved in both high and low stages of the secondary transmission. According to this, the vehicle speed (0.44~0.99k)
m/fl ) and reverse speed (0°25~0.96k
m/H'), which is not often applied, but on the other hand, it is difficult to obtain the necessary and finer-grained vehicle speeds such as rotary crushing work or plowing work. As is clear from a glance at Figure 2,
The vehicle speed according to the embodiment of the present invention is a fine vehicle speed (1,03 to 3.22 km/) suitable for rotary soil crushing work.
), and vehicle speed suitable for plowing (4.4 to 16.3
km/h) as well as trailer running vehicle speed (20,8~3
0.1km/H), reverse vehicle speed (4.5~10.6km
/H) can be obtained.

In addition, the vehicle speed when the tertiary transmission is connected in Fig. 4 2 (
0.44km/H) should be lowered to a vehicle speed suitable for trencher work or snow removal work (0.21~0.261u*/H).
) can of course be done.

According to the present invention, on the output side of the primary transmission that shifts the rotational power of the engine into a plurality of stages, there is provided a high-speed transmission section, a medium-speed transmission section that is slower than the high-speed transmission section, and a lower speed transmission section that is lower than the intermediate-speed transmission section. A secondary transmission is provided, each having a low-speed transmission section, and a transmission from the high-speed transmission section, medium-speed transmission section, and low-speed transmission section is provided from the output side of the primary transmission through the transmission shaft of the secondary transmission. Since high-speed, medium-speed, and low-speed power is transmitted to the differential mechanism, it is possible to obtain high, medium, and low vehicle speeds that are immediately responsive to work.

Furthermore, since a creep transmission is provided which has a creep transmission section which can be freely connected and disconnected only to the low speed transmission section of the secondary transmission and whose speed is lower than the low speed transmission section,
The advantage is that it is possible to obtain precise vehicle speeds in the originally required vehicle speed range, eliminating the confusing vehicle speeds that occur in conventional systems that unnecessarily increase the vehicle speed by providing a creep transmission as a so-called auxiliary transmission. There is.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic diagram of the overall structure, FIG. 2 is a detailed sectional view of the main part, FIG. 3 is a sectional view of the reversed part, and FIG. FIG. 4 is an explanatory diagram of vehicle speed according to a conventional example and an embodiment of the present invention. FIG. 4 1 shows the conventional vehicle speed, and FIG. 4 2 shows the vehicle speed according to the embodiment of the present invention. ■...Engine, 10...-growth gear, 16...
Primary transmission, 17-20. 22-25... - Growth speed gear, 21... - Growth speed subshaft, 28... Secondary transmission, 32, 39.41, 45.4764 , 66...
・Secondary transmission gear, 34...Secondary transmission subshaft, 42...
・-Adult linkage axis, 50.52.70...Shifter, 71・
...Creep transmission, 68,73.74...Gear for creep. Patent applicant Kubota Iron Works Co., Ltd. Figure 2 Figure 3

Claims (1)

[Claims] (1) On the output side 21 of the primary transmission 16 that shifts the rotational power of the engine 1 into multiple stages, there is a high-speed transmission part H, a medium-speed transmission part M whose speed is lower than the high-speed transmission part H, and a medium-speed transmission part H. A secondary transmission 28 is provided, each having a low-speed transmission section L having a lower speed than the section M. It transmits each high, medium, and low power from the speed system transmission section M and the low speed system transmission section L to the differential mechanism 29, and can be freely connected and disconnected only to the low speed system transmission section L in the secondary transmission 28. A tractor transmission characterized in that a creep transmission device 71 is provided, which has a creep transmission section 72 having a lower speed than a low speed transmission section L.