JPH035721Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial field of application] The invention is used mounted on a working vehicle such as an agricultural tractor. A shift operation lever that supports a plurality of shift sleeves that are slidably operated in a pattern and rotates the rotary cam plate is provided outside the transmission case, and these rotary cam plates and the shift operation lever are connected to the rotary cam. The plates are interlocked via a gear mechanism that expands the rotation angle, and the gear mechanism magnifies the amount of rotational operation by the shift operating lever and transmits it to the cam plate, thereby converting the rotational motion into a straight line. The present invention relates to a shift operation structure for a working vehicle, in which the cam surface inclination of the rotary cam that is switched to motion is set gently so that the shift sleeve can be smoothly and largely displaced and slid.

[Conventional technology]

In the shift operation structure of this type of work vehicle, in order to configure the shift operation position by the shift operation lever to be freely held and released, conventionally, a plurality of shift forks for the plurality of shift sleeves are attached to the same support shaft. Supported slidably in the axial direction,
A detent mechanism capable of holding and releasing the respective positions is provided between the support shaft and the plurality of shift sleeves.

[Problem that the invention attempts to solve]

However, in this case, multiple detent mechanisms must be provided for a single support shaft, which complicates the shift sleeve structure and increases the number of machining locations for the support shaft, increasing the number of machining steps. Therefore, it was disadvantageous in terms of production cost.

An object of the present invention is to provide a shift sleeve and a support shaft whose structure can be simplified by changing the position of the detent mechanism.

[Means for solving problems]

The characteristic configuration of the present invention is to support a plurality of shift sleeves that are slidably operated in a predetermined pattern by a rotary cam plate within the transmission case, and to rotate the rotary cam plate outward from the transmission case. A shift operation lever is provided, the rotary cam plate and the shift operation lever are interlocked and connected via a gear mechanism that expands the rotation angle of the rotary cam plate, and the large diameter gear of the gear mechanism and the transmission case A detent mechanism is formed between the detent mechanism and the wall surface, which allows the shift operation lever to maintain and release the shift position, and its effects are as follows.

[Effect]

In other words, we focused on the enlarged gear mechanism installed in the operation transmission system in order to operate multiple shift sleeves smoothly and by a sufficient sliding amount from a single shift operation lever, and By forming the detent mechanism between the inner wall surface of the case and the detent mechanism, it is possible to release the hold on the shift positions of the plurality of shift sleeves even if the detent mechanism is located at one location. Moreover, since the gear has a large diameter and the rotation angle of the shift operation lever is less than 360 degrees, the large diameter gear can be used as a partial gear. The detent mechanism can be provided on the outer circumferential surface of the gear other than the gear portion, and the detent mechanism can be effectively utilized without having to have a complicated configuration in which the detent mechanism is provided on the gear portion.

[Effect of idea]

As a result, by concentrating the setting locations of the detent mechanism on the large-diameter gear, the structure of the shift sleeve and support shaft can be simplified, making it advantageous to arrange them inside the transmission case. Since the detent mechanism is installed by effectively utilizing the advantage of the partial gear shape of It can be developed advantageously in terms of

〔Example〕

As shown in FIG. 6, an engine 2 and a main clutch housing 4 connected to the rear end of the engine 2 are mounted on the front part of the fuselage frame 1, and a transmission case 3 is installed at the rear of the fuselage frame 1.
There is a deck 4 which is substantially flat in the left and right direction above the middle part of the
The lift arm 7 is capable of traveling by supporting the machine body with the front and rear wheels 5 and 6, and has a control section 49 formed by extending the machine body 8, and drives a ground work device such as a tiller at the rear end of the machine body to raise and lower it, and the above-mentioned work. After transmitting power to the device
An agricultural tractor, which is one of the working vehicles capable of ground work, is configured with a protruding PTO shaft 8.

As shown in FIG. 5, the transmission structure inside the transmission case 3 is explained in detail.A first transmission shaft 10 is connected to the input shaft 9 so as to be relatively rotatable with their axes aligned with each other. The second transmission shaft 11 and the third transmission shaft 12 are arranged below the first transmission shaft 10, and the PTO is connected between the first transmission shaft 10 and the second transmission shaft 11.
A main transmission mechanism 14 is provided between the transmission mechanism 13 and the second transmission shaft 11 and the third transmission shaft 12 .

A fourth power transmission shaft 15 is coaxially connected with the third power transmission shaft 12 so as to be relatively rotatable, and an output gear 17 for the rear wheel differential mechanism 16 is fitted above the fourth power transmission shaft 15. The fifth power transmission shafts 18 are arranged respectively,
A forward/reverse switching mechanism 19 is provided between the third transmission shaft 12 and the fourth transmission shaft 15, and a forward/reverse switching mechanism 19 is provided between the third transmission shaft 12 and the fourth transmission shaft 15.
A sub-transmission mechanism 20 is provided between each of the transmission parts 8 and 8. A PTO system transmission shaft 22 is interlocked and connected to the rear end of the first transmission shaft 10 via a torque limiter 21, and this PTO system transmission shaft 22 extends rearward while bypassing above the rear wheel differential mechanism 16. broth,
The rear PTO shaft 8 is connected to this extended end via the deceleration mechanism 23.
are linked together. An output shaft 24 to the front wheel 5 is arranged at the lower end of the transmission case 3, and
A shift gear 5 provided at the rear end of this output shaft 24
0 switching operation enables switching between two-wheel drive using the rear wheels 6 and four-wheel drive using the front and rear wheels 5 and 6.

As shown in FIGS. 4 and 5, the main transmission mechanism 14 will be described in more detail.
A first shift sleeve S1 is provided between the small diameter gear 53 and the intermediate gear 52, and a first shift sleeve _S1 is provided between the small diameter gear 53 and the intermediate diameter gear 52, and the large diameter gear 51 and the subtransmission mechanism Output gear 5 to 20
A second shift sleeve S ₂ is provided between the gears 51 and 4, and by operating only one of the first and second shift sleeves S ₁ and S ₂ , this shift sleeve can be moved between the three large and small gears 51, It is constructed so that it can be selectively engaged with one of the gears 52 and 53 and can be switched to three speeds while preventing simultaneous engagement. The output gear 54 is interlocked with the input gear 55 of the auxiliary transmission mechanism 20 via an idle gear (not shown) and an intermediate gear 40 loosely fitted to the output shaft, and is interlocked with the input gear 55 of the auxiliary transmission mechanism 20 by the switching operation of the shift sleeve of the forward/reverse switching mechanism 19. Therefore, the transmission state is changed over.

Next, the operating structure of the main transmission mechanism will be explained.

As shown in FIGS. 1 to 4, the main transmission mechanism 1
Shift forks 30 and 31 that operate the two shift sleeves S ₁ and S ₂ of No. 4 are slidably supported on a common fixed support shaft 32, and cam followers 33 and 34 each consisting of a rotating roller are mounted on the outside of the case. It is mounted towards. A large opening 35 is formed in the left side wall of the transmission case 3, and a cover 36 that covers this is provided with a disc-shaped rotating cam plate 38 having a cam groove 37 formed on the side surface for engaging the cam followers 33, 34. It is pivoted.
Further, the cover 36 supports an operating shaft 39 which is rotatably operated from the outside, and this shaft 39 and a pivot shaft portion 38A of the rotary cam plate 38 are connected by a gear mechanism 29 consisting of large and small gears 41 and 42. It is linked to speed increase. The arm 43 attached to the outer end of the operating shaft 39 is in the first speed at the _P1 position shown in FIG. 3, the second speed at the _P2 position, and the third speed at the _P3 position.
In addition, the shape of the cam groove 37 is set so that neutrality can be obtained at each N position. A lever support shaft 45 is horizontally fixed to a frame 44 attached above the transmission case 3, and the arm 43 is connected to a main shift lever 46, which is one of the shift operation levers, supported on the left end of the lever support shaft 45. Linked with Rod 47,
The main shift lever 46 is configured to perform a three-stage main shift operation by linearly swinging the main shift lever 46 back and forth.

In addition, 28 in the figure is an operation lever for the auxiliary transmission mechanism 20,
27 is an operating lever for the PTO transmission mechanism 13.

A large diameter gear 4 fitted to one end of the operating shaft 39
1 is provided with a gear portion 41A corresponding to the operating rotation angle of the main shift lever 46, occupying approximately half the circumference, and an engagement member recessed radially inward into the outer circumferential surface corresponding to the remaining half circumference. A hole 41a is provided. A spring ball mechanism 26 is provided on the inner wall surface 36A of the cover 36 corresponding to the engagement hole 41a.
a detent mechanism 25 that can hold and release the operating position of the main shift lever 46 by the engagement between the ball 26 and the engagement hole 41a in conjunction with the switching operation of the main shift lever 46; has been configured.

[Another example]

B. The detent mechanism 25 of the above embodiment may be applied to other transmission mechanisms other than the main transmission mechanism 14.

○B The above embodiment may be applied to other working vehicles such as transport vehicles other than agricultural tractors.

[Brief explanation of the drawing]

The drawings show an embodiment of the speed change operation structure for a working vehicle according to the present invention, in which FIG. 1 is a vertical sectional side view of a rotary cam plate and an enlarged gear mechanism, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 4 is a longitudinal sectional view showing the operating state of the main transmission mechanism, FIG. 5 is a schematic diagram of the transmission mechanism inside the mission case, and FIG. 6 is a side view showing the operating lever provided on the outer surface of the transmission case. is a side view of the tractor. 3...Mission case, 25...Detent mechanism, 29...Gear mechanism, 36A...Inner wall surface, 38
... Rotating cam plate, 41 ... Large diameter gear, 46
...Shift operation lever, _S1 , _S2 ...Shift sleeve.

Claims (1)

[Scope of utility model registration request] The rotating cam plate 3 is inside the transmission case 3.
8 to support a plurality of shift sleeves S ₁ , S _{2 .} . . which are slidably operated in a predetermined pattern, and
A shift operation lever 46 for rotating the rotary cam plate 38 is provided outside the transmission case 3, and a gear mechanism 29 for connecting the rotary cam plate 38 and the shift operation lever 46 to increase the rotation angle of the rotary cam plate 38 is provided. Further, a detent mechanism 25 is formed between the large diameter gear 41 of the gear mechanism 29 and the inner wall surface 36A of the transmission case 3, and is capable of holding and releasing the shift position by the shift operation lever 46. The gear change operation structure of a working vehicle.