JPS5941171Y2 - Agricultural tractor park lock device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a park lock device for an agricultural tractor, that is, a lock device that prevents the tractor from moving when parked.

This kind of park lock device is generally known, but in the conventional device, the park lock is placed in front of the main transmission, so when the main transmission is in the neutral position, the park lock does not function. The drawback was that it didn't.

In addition, it is common for tractors to have both a main gear and a auxiliary gear in order to have a large number of gears to accommodate various types of work.In this case, if a park lock is provided on the main gear, However, if the sub-shift is in the neutral position, it will still not function.

One of the features of the present invention is that such inconveniences are eliminated.

Furthermore, as a park lock device, it is conceivable that the gear for the gear shift shaft is engaged with an engaged member fixed to a transmission case, etc., but the present invention does not require structural modification to attach such an engaged member. To provide a park lock device which is compact and can be easily attached to an existing transmission case.

The structure of the present invention will be explained based on drawings showing one embodiment. Fig. 1 shows the entire agricultural tractor, in which an engine 1 is mounted on the front part of the machine body, a clutch housing 2 is mounted on the rear part of the machine, and a clutch housing 2 is mounted on the rear part of the machine. A transmission case 3 is connected to the rear of the transmission case 3, and a rear case 4 is connected to the rear of the transmission case 3, and the power from the engine 1 is
The transmission is transmitted via the main clutch in the clutch housing 2 to the mission mechanism in the mission case 3, and is configured to drive the rear wheels 5 from the mission mechanism via the differential device in the rear case 4.

FIG. 2 shows the details of the mission mechanism inside the mission case 3. The mission case 3 is divided into a main transmission chamber 7 on the front side and an auxiliary transmission chamber 7 on the rear side, with an intermediate wall 6 provided at the center as a boundary. It is divided into chamber 8.

9 is a PT whose shaft is mounted through this mission case 3.
It is an O drive shaft, and its front end is interlocked and connected to the power take-off part of the engine 1, and its rear end is connected to a PTO transmission mechanism part (not shown) in a rear case 4 connected to the rear part of the mission case 3. Ru.

A manpower shaft 10 is loosely fitted and supported in the front half of the PTO drive shaft 9 in the main transmission chamber 7, and similarly to the PTO drive shaft 9, the manpower shaft 10 is used for extracting power from the engine 1. It receives power from the engine 1 by being interlocked with the engine 1, and on its outer periphery, there are four large and small gears 11,
12.13°14 are provided integrally.

Similarly, in the main transmission chamber 7, below this human power shaft 10, an intermediate first shaft 15 is mounted between the front wall of the mission case 3 and the intermediate wall 6. ,
Four loosely fitted gears 16, 17, and 18 that are always meshed with or interlocked with the gears 11, 12, 13, and 14 of the human power shaft 10, respectively.
．． 19, and two twin gears 20 and 21 that are slidably spline-fitted are attached.

In addition, the gear 16 attached to the frontmost part is for reversing,
A reverse idle gear (not shown) is provided between the reverse gear 16 and the gear 11 at the frontmost portion of the input shaft 10 so as to be constantly meshed therewith.

Reference numerals 22 and 23 shown in FIGS. 2 and 3 are two main speed shift fork shafts provided above the main transmission chamber 7 so as to be movable in the axial direction. A shifter 25 and a shift fork 26 are engaged with the tip of the gear change lever 24a, and a shifter 27 and a shift fork 26 are connected to the other shift fork shaft 23. fork 28
These shift forks 26 and 28 are provided with
They are respectively engaged with double gears 20.21 of the intermediate first shaft 15, and the shift forks 26.28 engage the two gears 20.21.
By sliding the continuous gear 20.21, the loosely fitted gear 16.1
7.18.19 Internal meshing part 29.30.31.
32, thereby performing a main gear shift of three forward speeds and one reverse speed.

On the other hand, in the sub-transmission chamber 8, an intermediate second shaft 33 is mounted on the rear half of the PTO drive shaft 9 so as to be relatively rotatable. axis 33
There are three speed change gears 34, 35, and 36, large and small, that rotate integrally with the gear.
4 is the intermediate first shaft 15 protruding into the sub-speed chamber 8;
It is always engaged with a pinion 37 at the rear end and receives the rotational power of the main gear shift.

Reference numeral 38 denotes an internal meshing portion formed on the inner circumferential surface of the rear end of the intermediate first shaft 15.

39 is a drive pinion shaft as an output shaft disposed below the second intermediate shaft 33 and parallel to the second shaft 33, and its front end rotates relative to the rear end of the first intermediate shaft 15. The rear end is fitted with a thrust bearing 41.4 on a cylindrical shaft 40 that passes through the mission case 3.
The cylindrical shaft 40 is fitted into the support wall 42 at the front of the rear case 4, and the flange portion 43
At this point, it is fixed with a bolt 44.

44a is a rotation stopper for the bolt 44. Reference numeral 45 indicates an annular presser foot screwed onto the drive pinion shaft 39 to support the thrust bearing 41.41.

46 also connects the rear end small diameter portion 46a to the cylindrical shaft 40.
It is an engaged member that is fitted thickly at the front end and has an internal engagement part 47 formed on the inner peripheral surface of the front end, and is fixed to the cylindrical shaft 40 with a bolt 49 at a flange part 48 formed on the outer periphery thereof so as not to rotate. be done.

On the other hand, the drive pinion shaft 39 has one loosely fitted gear 50 and two double gears 51 and 5 that are slidably spline-fitted and rotate integrally with the drive pinion shaft 39.
A small diameter gear 53 formed on the rear double gear 52 of the two double gears 51 and 52 is attached to 2 and force S.
It is configured to be able to mesh (engage) with the internal meshing portion 47 of the engaged member 46 .

That is, the small-diameter gear 53 provided as a part of the sub-shift gear 64 serves as an engaging member that engages with the engaged member 46, and thereby the park lock device described later is operated. It consists of

54 is a pinion formed at the rear end of the drive pinion shaft 39, and this pinion 54 is constantly connected to the rear wheel 5 via a differential device (not shown) in the rear case 4.

Next, 55 and 56 shown in Fig. 3 are mission case 3.
Two shift fork shafts for auxiliary transmission are provided on the upper part so as to be freely movable in the axial direction, and these shift fork shafts 55.
A shifter 57.58 that engages with the tip of the sub-shift lever 24b (FIG. 1) and a sub-shift shift fork 59.60 are attached to the shift fork 56, respectively. Each is engaged with a double gear 51, 52 of the drive pinion shaft 39.

The sub-transmission mechanism based on the above configuration performs three-speed gear shifting and one park lock. First, one gear 61 of the double gear 51 on the front side is moved to the middle gear by one shift fork 60. When the other gear 62 is engaged with the internal meshing portion 38 of the first shaft 15, the force speed H1 is medium speed M.
Next, when the other shift fork 59 engages one large diameter gear 64 of the rear double gear 52 with the small diameter gear 36 of the intermediate second shaft 33, the speed is low; By meshing the other small diameter gear 53 with the internal meshing portion 47 of the engaged member 46, the drive pinion shaft 3
9 prevents rotation of the rear wheel 5 connected to the drive pinion shaft 39, thereby performing a park lock P that prevents the tractor from moving.

These changes are shown in FIG. 4 by the movement of the lower end of the sub-shift lever 24b.

The present invention has the above-mentioned configuration.In this way, in this invention, an engaging member is attached to the output shaft of the auxiliary transmission to lock the output shaft of the auxiliary transmission, so that only the main transmission can be changed. Moreover, the park lock can be performed even when the sub-shift is in neutral, and it can be used regardless of the position of the main shift.

Furthermore, in the present invention, the engaged member is fixed to the flange of the cylinder shaft fixed to the wall of the mission case, and therefore, as shown in Japanese Utility Model Publication No. 4947162
Compared to the case where the engaged member is fixed to the shift rod,
This has the effect of firmly locking the shift rod without causing any twisting.

On the other hand, the invention of the present invention in which an engaged member having an internal meshing part etc. is supported by a transmission case is also disclosed in Japanese Utility Model Application Publication No. 106431/1983; In known examples, it is fixed to the mission case wall directly by bolting, etc. Therefore, when attaching such an engaged member to the mission case inner wall, as in the present invention, the flange part of the cylinder shaft etc. If so, the flange portion must be further expanded to the H-rule for mounting the engaged member, which has the drawback of increasing the size of the structure and increasing costs.

On the other hand, in the present invention, since it is fixed to the flange part with bolts, there is no such drawback1, and furthermore, there is no need to open a screw hole into the mission case wall for mounting the engaged member. Therefore, no machining is required on the mission case side, and if space is available, it can be installed in an existing mission case by simply replacing the cylinder shaft.

Furthermore, in the invention of the above-mentioned Japanese Utility Model Publication No. 49-47162,
Since the engaging member for the speed change shaft and the engaging member on the shift rod must be slid simultaneously so as to engage with the speed change gear, the structure of the operating system becomes complicated.

On the other hand, in the device disclosed in Japanese Utility Model Application Publication No. 51-106431, the sliding operation of the engaging member is performed by a hydraulically actuated piston, which has the drawback that the structure of the operating system is complicated and the cost is high. In the present invention, a shift fork that does not rely on hydraulic pressure is directly engaged with the engaging member, and sliding operation is performed by this shift fork, and since it is only necessary to slide one engaging member, the structure is simple. It has the effect of being easy and inexpensive to manufacture.

Further, in this case, the point that the engaging member is slid by a shift fork that does not rely on hydraulic pressure is similar to the invention of Japanese Utility Model Publication No. 4947162, but the structure in which the engaging member on the shift rod is meshed with the speed change gear is changed. Therefore, the engaging member and the speed change gear must be in a position where they can engage with each other, that is, the speed change gear must be located in close proximity to the shift rod. When installing it on the output shaft of a sub-transmission in a car, there is an inconvenience that it cannot be installed unless the output shaft and the shift rod are close to each other.

On the other hand, Utility Model Application No. 51-106431 cannot be installed in a conventional transmission mechanism using an existing shift fork.

On the other hand, in the present invention, there is no such restriction because the engaging member is only provided on the output shaft. It is only necessary to engage the gear with a conventional shift fork, and it has the effect of being able to be installed in existing transmission mechanisms regardless of the position of the shift rod.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of the tractor, Fig. 2 is a vertical sectional view of the transmission mechanism, Fig. 3 is a partially omitted plan view of the upper part of the transmission mechanism, Fig. 4 is a system diagram showing the operating position of the auxiliary transmission, 5
The figure is a sectional view taken along the line A--A in FIG. 2. 3...Mission case, 5...Rear wheel, 39...Drive pinion shaft, 46...
...Engaged member, 53...Small diameter gear, 40.
... cylinder shaft, 41 ... bearing, 43 ...
...Flange part, 44.49...Bolt, 59
...Shift fork, 64...Sub-shift gear.

Claims (1)

[Scope of utility model registration request] In a tractor mission mechanism that is equipped with a plurality of gear groups in a mission case to perform main and sub-shifts, the output shaft of the sub-shift is mounted via a bearing by a cylindrical shaft passing through the mission case. , and the cylindrical shaft inner end flange portion is fixed to the mission case wall with a bolt, and a slidable engagement member that rotates integrally with the output shaft is attached to a part of the sub-transmission gear. At the same time, an engaged member that can be directly engaged with the engaging member is bolted to the flange portion of the cylinder shaft, and the engaging member is slid by a shift fork that engages with the sub-shift gear. A park lock device for an agricultural tractor, characterized in that it is operable.