JPH063214Y2 - No clutch transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a traveling transmission mainly used for agricultural or earthworking work vehicles, and more specifically to gear shifting without requiring a clutch operation by a pedal. The present invention relates to a so-called non-clutch transmission.

[Conventional technology]

As non-clutch type transmission, electromagnetic clutch,
Alternatively, it is known that a shift lever is provided with a clutch operation switch that is operated and operated by an electric actuator so that the clutch can be turned on and off at the same time when the shift lever is operated.

[Problems to be solved by the invention]

However, for work vehicles used under severe working conditions such as agricultural and earthwork, the structure that electrically engages and disengages the clutch has many problems in reliability and durability, and in terms of cost. It was expensive and easy to use, and there were practical difficulties.

The present invention focuses on the fact that many agricultural and earthmoving work vehicles are equipped with a hydraulic device, and configures the clutch to be hydraulic, and reasonably links the operating structure of the clutch to the gear shift mechanism. With high reliability and durability, and
An object of the present invention is to provide a non-clutch type speed change device which has a relatively simple structure and can be manufactured at low cost.

[Means for solving problems]

The characteristic configuration of the present invention made to achieve the above object is to form an oil passage communicating with a hydraulic clutch inside a fork shaft slidably fitted with a shift fork, and to provide an opening communicating with the oil passage. The end is provided on the outer peripheral surface of the fork shaft,
When the shift fork is in the normal gear shift position, the opening end is closed by the boss portion of the shift fork, and when the shift fork is disengaged from the gear shift position, the oil discharge port formed in the boss portion and the open end overlap. The oil passage is opened to the inside of the mission case, the boss portion is provided with a detent spring ball, and the outer peripheral surface of the fork shaft is provided with a ball positioning recess corresponding to each shift position and the recess. It is a point that a notch is formed across.

[Action]

According to the above configuration, when the shift fork is in the regular shift position, that is, when the spring ball is engaged with the ball positioning recess formed in the fork shaft,
Since the opening end is closed by the boss portion of the shift fork, the oil passage is not opened, and the hydraulic clutch maintains the engaged state.

Further, when the shift fork is displaced from the normal gear shift position, that is, when the spring ball escapes from the recess, the oil passage is opened because the opening end overlaps with the oil discharge port formed in the boss. As a result, the operating pressure of the hydraulic clutch decreases and the clutch is disengaged. Then, the gear disengagement in the previous shift stage, the shift to the neutral state, and the gear mesh in the next shift stage are performed in the clutch disengaged state, and when the shift member reaches the next shift position, the hydraulic clutch automatically restarts. It enters into the state and the transmission state is brought.

Further, even if the shift fork is further out of the normal position and the spring ball is in the state of coming out of the recess, the spring ball comes into contact with the notch formed between the adjacent recesses, and the boss portion and the fork shaft. The relative rotation with respect to is restricted. Therefore, even if the fork shaft is not locked to the transmission case, the fork shaft does not rotate due to transmission vibration or the like, and therefore the opening end of the fork shaft overlaps well with the oil discharge port of the boss portion. it can.

[Effect of device]

Therefore, according to the present invention, since the hydraulic clutch is used as the clutch that is automatically input for the non-clutch gear shifting, it can be reliably used even in the work vehicle used in the soft ground with a lot of mud and water, and the uneven ground with a lot of ups and downs and irregularities. It can be operated at a low cost and can be implemented relatively inexpensively since it does not use an electric control device. Moreover, since the relative rotation between the fork shaft and the boss portion is always regulated, the opening / closing error of the oil passage is reduced, the operation of the clutch is ensured, and its reliability is high.

〔Example〕

FIG. 4 illustrates a combine traveling speed change device applied to the present invention.

The transmission case (1) is provided with an input shaft (2) as a constant rotation shaft which is linked to a belt (not shown) as an engine, and a driving gear (3) loosely fitted to the input shaft (2) and the input shaft (2). ) Is provided with a multi-plate hydraulic clutch (4).

The drive gear (3) is interlocked with the gear (7) fixed to the speed change shaft (6) via the intermediate transmission gear (5),
By slidingly operating the two-stage shift gear (8), which is spline-fitted to (6), a main gear transmission mechanism (9) that shifts three forward gears and one reverse gear is configured. The figure shows the neutral state.

This main gear transmission (9) has the shift gear (8) in the neutral position.
By shifting the gear (8a) to the right from (N) and engaging the small gear (8a) with the gear (11) fixed to the fourth shaft (10), the first forward speed (F ₁ ) can be obtained, and the shift gear (8) Shift further to the right to engage the large gear (8b) with the gear (12) fixed to the fourth shaft (10) to move forward 2
A gear (14) in which the speed (F ₂ ) is obtained, and the claw (13) formed on the side surface of the shift gear (8) is loosely fitted to the transmission shaft (6) by shifting to the right.
3rd forward speed (F ₃ ) is obtained by engaging with the claw (15) of
Further, the reverse gear can be obtained by shifting the shift gear (8) to the left from the neutral position (N) and engaging the small gear (8a) with the gear (17) of the third shaft (16).

The idle gear (14) of the speed change shaft (6) is always engaged with the gear (18) fixed to the fourth shaft (10), and the reverse gear (17) is the forward first speed gear ( It is geared to 11).

Further, the power of the fourth shaft (10), which has been shifted by the main gear transmission mechanism (9), is transmitted to the axle located below in the figure via the auxiliary gear transmission mechanism (19). Incidentally, the auxiliary gear speed change mechanism (19)
Is capable of shifting between high and low by shifting the shift gear (20) left and right.

The hydraulic clutch (4) is adapted to be engaged and disengaged in conjunction with the shift operation of the main gear transmission mechanism (9).
The structure will be described.

The hydraulic clutch (4) is urged by an internal spring (21) to disengage, and an oil passage (2
2) is formed from one end of the input shaft (2). Further, an oil passage (26) communicating with the hydraulic pump (23) is formed on the side wall of the mission case (1), and the oil passage (26) is the in-shaft oil passage (22).
And is configured to supply pressure oil to the hydraulic clutch (4).

The pump (23) is directly connected to the on-board engine and sucks the mission oil.

The first shift fork (27), which operates the shift gear (8) of the main gear speed change mechanism (9), is externally fitted and supported by a fork shaft (28) supported and fixed to the mission case (1) to change gears outside the case. The lever is operated to perform an arbitrary shift operation, and the boss (27A) of the first shift fork (27) is provided with a spring ball (29) provided for detent as described above.
It is adapted to be positioned and held at each shift position (R), (F ₁ ), (F ₂ ), (F ₃ ) and neutral position (N). On the other hand, the second shift fork that operates the shift gear (20) of the sub gear transmission mechanism (19)
The (30) is externally fitted and supported by a fork shaft (31) supported and fixed to the mission case (1), and is arbitrarily shifted by the operation of the auxiliary shift lever outside the case. Spring provided on the boss (30A)
The ball (29) is positioned and held at the high and low speed change positions (f ₁ ) and (f ₂ ).

The main gear speed change mechanism (9) will be described in more detail. As shown in FIGS. 1 and 2, the first shift fork (27) is provided on the fork shaft (28) at each shift position (R), (F ₁ ), (F ₂ ), (F ₃ ), and recesses (39) for engaging the spring balls (29) when in the neutral position (N) are provided at the respective positions. And the spring ball over the recesses (39).
The (29) is guided from the recess (39) to the adjacent recess (39), and the fork shaft (28) and the boss (2) of the first shift fork (27) are guided.
The notch (40) is formed to restrict the relative rotation with (7A). The fork shaft (31) on the side of the auxiliary gear transmission mechanism (19) is also provided with a notch (40) over the recess (39) for the same purpose as described above. The first shift fork (27) and the fork shaft (28) as well as the second shift fork (30) and the fork shaft
Together with (31), control valve mechanisms (V ₁ ) and (V ₂ ) that control the supply and discharge of each pressure oil to and from the hydraulic clutch (4) are configured.

That is, the oil passage formed on the side wall of the mission case (1)
(26) is an oil passage (2
6a) and the oil passage (26
b) and the oil passages in both shafts (26a),
The ends of (26b) are opened to the outer peripheral surfaces of the respective fork shafts (28), (31), while the first and second shift forks (27), (30) are provided.
The bosses (27A) and (30A) of the shafts have their respective oil passages (26a) and (26b) in the shaft.
Of the oil drain ports (27a), (30a) that connect the open ends (28a), (3a) of the
a) is drilled and the first shift fork (27) is at each shift position.
When it is at (R), (F ₁ ), (F ₂ ), (F ₃ ), the opening end (28a) is closed, and the second shift fork (30) is set at each shift position (f ₁ ), (f ₂ ), The open end (31a) is closed.

Therefore, when the first shift fork (27) or the second shift fork (30) is in a certain shift position, the opening end (28a
Alternatively, 31a) is closed, so that the pressure oil from the hydraulic pump (23) is supplied to the hydraulic clutch (4) via the in-shaft oil passage (22), and the hydraulic clutch (4) is in the engaged state, Transmission is performed at the gear shift.

Then, when the first shift fork (27) or the second shift fork (30) is slightly moved from a certain shift position, the opening end (28a
Or 31a) is opened, the pressure oil of the hydraulic pump (23) escapes into the transmission case (1), the clutch pressure is reduced accordingly, and the hydraulic clutch (4) is automatically disengaged.
Gear shift is performed with the transmission cut off. When the gear shift is complete and the next gear position is reached, the open end (28
hydraulic clutch (4) when a or 31a) is closed
Is automatically entered.

The hydraulic circuit is shown in FIG.

The neutral oil discharge passage of the three-position switching valve (33) which controls the forward and reverse operation and stop of the reaper section lifting cylinder (32) is connected to the hydraulic clutch (4) as the oil passage (26) for clutch operation. At the same time, the pressure oil supply oil passage (34) that connects the hydraulic pump (23) to the three-position switching valve (33) and the neutral oil discharge passage (26) are connected to each other by the necessary pressure for raising the cutting portion (for example, 80 kg / cm ² ) Is connected via a high pressure relief valve (35) set to pressure. The neutral oil drain passage (26) is connected to the neutral oil drain passage (26) only by the hydraulic clutch (4) when the main gear shift lever or the auxiliary gear shift lever is in the normal gear shift position. State, the neutral oil discharge passage (26) and the hydraulic clutch
The control valve mechanisms (V ₁ ) and (V ₂ ) having the above-mentioned configuration are provided for communicating (4) with the tank to bring the clutch into the disengaged state. Furthermore, in the neutral oil discharge passage (26) of the control valve mechanisms (V ₁ ) and (V ₂ ), a low pressure relief valve (for obtaining a predetermined clutch operating pressure (for example, 20 kg / cm ² ) is provided. 37) is provided.

Incidentally, (38) is an accumulator for softening the impact when the clutch is engaged.

In implementing the present invention, the notch (40) may be a groove having a semi-circular cross-section that can be engaged with the spring ball (29).

[Brief description of drawings]

The drawings show an embodiment of a clutchless transmission according to the present invention. Fig. 1 is a sectional view of a clutch operating control valve, Fig. 2 is a sectional view taken along line II-II of Fig. 1, and Fig. 3 is a hydraulic circuit. FIG. 4 and FIG. 4 are exploded sectional views of a traveling transmission for a combine to which the present invention is applied. (1) …… Mission case, (4) …… Hydraulic clutch, (26
a) …… Oil passage, (27) …… Shift fork, (27A) …… Boss part, (27a) …… Oil drainage port, (28) …… Fork shaft, (28a) ……
Open end, (29) …… Spring ball, (39) …… Concave, (4
0) …… Notch.

Claims (1)

[Scope of utility model registration request] 1. An oil passage (26a) communicating with a hydraulic clutch (4) is formed inside a fork shaft (28) slidably fitted with a shift fork (27), and the oil passage (26a) is formed. Open end (2
8a) is provided on the outer peripheral surface of the fork shaft (28), and when the shift fork (27) is in the normal shift position, the opening end (28
a) is closed by the boss portion (27A) of the shift fork (27), and when the shift fork (27) comes out of the shift position, the oil drain port (27a) formed in the boss portion (27A) and the opening end ( 28a)
And the oil passage (26a) are configured to open into the mission case (1), and the boss (27A) is provided with a spring ball (29) for detent.
A clutchless transmission in which a recess (39) for ball positioning corresponding to each shift position and a notch (40) extending over the recess (39) are formed on the outer peripheral surface of (28).