JP3294650B2 - Transmission structure of agricultural work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission system between an engine and a power take-off shaft, which is provided with a friction type hydraulic clutch which is urged to a clutch disengagement side and operated to enter a clutch by supplying hydraulic oil. Related to the transmission structure of an agricultural work vehicle.

[0002]

2. Description of the Related Art Conventionally, in a transmission structure of an agricultural work vehicle, conventionally, when a structure is provided as an external work device, for example, a lawn mowing work device and driven by a power take-off shaft, the driven side is disengaged when a hydraulic clutch is disengaged. In some cases, the rotational state may be continued due to the driving inertia force of the lawn mowing device. In order to surely stop the rotation of the power take-off shaft during such a clutch disengagement operation, the hydraulic clutch is biased toward the clutch disengagement side. Using the spring force of the spring for
A structure was proposed in which a friction type brake mechanism for braking the driven side was provided.

[0003]

However, if a structure is employed in which the driven member is pressed against the fixed member and braked, as in the above-described conventional structure, the co-rotational rotation and excessive rotation due to inertial force as described above are suppressed. However, the driven side is braked to a non-rotatable state.

For this reason, the rotation phase of the engagement projection formed on the power take-out shaft at a predetermined pitch in the circumferential direction is different from the rotation phase of the engagement concave portion in the power intake portion on the external working device side. In such a case, for example, in a working device such as the above-described lawn mowing work device or the like, in which the driving unit cannot be rotated while the grounding state is maintained, the engagement protrusion and the engagement concave portion may not be engaged. There was room for improvement.

Therefore, as shown in, for example, Japanese Patent Application Laid-Open No. 4-113935, a hydraulic braking mechanism having a structure different from the hydraulic clutch is provided, and a state in which the clutch is disengaged and the braking action does not work can be realized. Such a configuration of a hydraulic circuit was considered.

However, when this improved structure is applied to the above-described transmission system, there is a disadvantage that a brake member, a brake hydraulic cylinder, a hydraulic pipe and the like are required separately from the hydraulic clutch, which complicates the structure and increases the cost. .

An object of the present invention is to prevent the driven side from rotating due to inertia when the clutch is disengaged, and to make it possible to rotate the transmission lower side within a certain angle range even during the clutch disengagement operation. Therefore, the above-mentioned situation in which the bite cannot be performed can be avoided with a simple structure.

[0008]

According to a first aspect of the present invention, there is provided a technical means for achieving the above object, wherein power from an engine is urged to a clutch disengagement side and hydraulic oil is supplied. In the transmission structure of an agricultural work vehicle, a transmission system is configured to supply a power take-out shaft via a friction hydraulic clutch that is operated to be engaged by a clutch.
When the hydraulic piston in the friction type hydraulic clutch is operated to return to the clutch disengagement position, a braking mechanism that interlocks with the hydraulic piston and has a brake mechanism that presses against the fixed side braking member by the clutch disengaging urging force to perform braking,
The fixed-side braking member has a predetermined rotation angle range with respect to the transmission case-side fixed member that supports the fixed-side braking member.
Support through rotation restricting means that allows relative rotation only within the enclosure.
The point is that you have .

A second aspect of the present invention is the same as the first aspect of the invention, except that the power from the engine is urged toward the clutch disengagement side and the clutch is operated by supplying hydraulic oil to operate the clutch. A transmission system for supplying the power to the power take-off shaft, and in a transmission structure of an agricultural work vehicle having a gear shift type transmission mechanism on the lower side of the transmission of the hydraulic clutch, a hydraulic piston in the friction type hydraulic clutch is moved to a clutch disengaged position. When the return operation is performed, a braking mechanism that is interlocked with the hydraulic piston is provided with a brake mechanism that presses against and brakes the fixed-side braking member by a clutch-disengaging urging force, and the fixed-side braking member is moved to the fixed-side braking portion.
Respect to the transmission case-side fixing member which supports the timber, where
A rotation restricting hand that allows relative rotation only within the fixed rotation angle range
The point is that they are supported via steps .

[0010] Similarly, the characteristic constitution of the invention described in claim 3
Is a transmission structure for an agricultural work vehicle according to claim 1 or 2.
The predetermined rotation angle range is set to about 60 degrees.
You.

[0011]

When the supply of hydraulic oil to the hydraulic clutch is stopped and the clutch is disengaged, the hydraulic piston is returned to the clutch disengaged position by the biasing force of the clutch disengagement, and the braking action unit linked to the hydraulic piston is pressed against the fixed-side braking member. The brake is applied to the driven side. As a result, the rotation of the power take-out shaft due to the inertial force is prevented.

The fixed side braking member is allowed to rotate within a predetermined angle range in a direction opposite to the direction of driving rotation by the engine. Even in the state, when the transmission shaft on the lower side of the transmission of the hydraulic clutch is relatively rotated within a predetermined range, the rotation phase is slightly shifted, so that the engagement can be performed and the connection with the external working device can be smoothly performed.

Further, in the clutch disengaged state, the locking piece of the braking member is always in contact with the fixed portion on the transmission case side due to the corotation in the friction portion, so that the braking member is subjected to an impact at the next clutch engagement operation. There is no stoppage of contact.

Further, when a gear shift type transmission mechanism is provided on the lower side of the transmission of the hydraulic clutch, the clutch disengaging urging force of the hydraulic piston in the hydraulic clutch is effectively used to generate power. The braking function of the take-out shaft can be obtained, and the shift operation of the transmission mechanism located on the lower transmission side can be performed even in the clutch disengaged state.

Further, as described in claim 3, the location
When the fixed angle range is set to about 60 degrees, the clutch is disconnected.
The lower transmission side transmission mechanism is engaged with the above-mentioned engagement protrusion and engagement recess.
In the required range, such as when
Relative rotation can be made possible,
It is also possible to prevent the rotation amount from becoming too large.

[0016]

According to the configuration of the invention according to claim 1,
While it is possible to reliably suppress the entrainment of the driven side and the inertial rotation of the external working device during the disengagement operation of the friction type hydraulic clutch, the rotation angle is within a predetermined angle in the direction opposite to the driving rotation direction by the engine. Since the rotation is allowed, the power take-out shaft can be relatively rotated to some extent, and there is an effect that the work of connecting the power take-out shaft and the external working device can be performed smoothly.

According to the second aspect of the present invention, the braking function of the power take-off shaft can be obtained by effectively utilizing the clutch-disengaging biasing force of the hydraulic piston in the hydraulic clutch, and the brake mechanism is required. The simple improvement of the fixed-side braking member makes it possible to perform a shift operation of the transmission mechanism located on the lower transmission side even in the clutch disengaged state, and to provide a transmission structure having excellent operability by a simple structure. Reached.

Further, as described in claim 3, the predetermined angle
When the degree range is set to about 60 degrees, the clutch
Correction of rotational phase shift in lower transmission mechanism
Relative rotation required in a proper range can be permitted.

[0019]

Embodiments will be described below with reference to the drawings.

FIG. 1 shows an agricultural tractor which is an example of an agricultural work vehicle. This agricultural tractor transmits the power of an engine 1 mounted on the front of the fuselage to front and rear wheels 3 and 4 via a transmission case 2, and also has a rear power take-out shaft 5 provided at the rear of the machine and a central power take-out provided at the lower part of the machine. A transmission system is configured to supply power to the shaft 6.

More specifically, as shown in FIG. 2, the power of the engine 1 is input to a gear shift type main transmission mechanism 9 via a main clutch 7 and a cylinder shaft 8, and the speed change output is output from the sub transmission mechanism 1
The vehicle traveling drive system is configured to be supplied to the rear wheel differential mechanism 11 via the front wheel 0 and to the front wheels 3 via the front wheel speed increasing mechanism 12. Further, an input shaft 13 to which the power of the engine 1 is directly supplied is idlely fitted to the cylinder shaft 8, and the power take-off shafts 5, 5 are connected via a hydraulic PTO clutch 14 and a gear shift operation type PTO transmission mechanism 15. A PTO transmission system is configured so that power is supplied to 6.

Next, the mounting structure of the PTO clutch 14 will be described. The PTO clutch 14 is constituted by a multi-plate friction type hydraulic clutch, and is configured to be mounted in the transmission case 2 in an assembled state that is assembled in advance in a unitized state.
A large opening 22 on the upper side of the transmission case 2
Can be installed from the upper side. That is,
As shown in FIG. 3, the driven side friction plate 23 is rotatably engaged with the driven side, and a driven member 25 fitted outside the spline to the driven shaft 24 is supported by the support case 2 via a bearing 26.
7, the unit is supported in a unit state while being rotatably fitted inside. Further, a hydraulic piston 28 is slidably fitted in a cylindrical space formed by the drum portion 25a and the spline boss portion 25b of the driven member 25, and is formed by piercing the support case 27 and the driven member 25. Oil passage L1,
The hydraulic oil is supplied to the oil chamber R of the hydraulic piston 28 via L2. The hydraulic piston 28 is configured to be urged toward the clutch disengagement side by a compression spring 30 interposed between the hydraulic piston 28 and a bearing 29 that is fitted and fixed to the spline boss 25b.

The unitized PTO clutch unit is inserted from the upper side through an opening 22 formed largely in the upper part of the transmission case 2 and, as shown in FIGS. The two side flange portions 27a, 27a are
It is erected, connected and fixed over the step portion between the first and the first. After the clutch unit is mounted, the opening 22 of the transmission case 2 is closed by the cover 32.

The operating oil for the PTO clutch 14 is configured to be supplied with return oil of a hydraulic circuit for power steering, and its switching control valve 33 is directly bolted to a mounting seat 34 formed on the side of the transmission case 2. The oil passage between the control valve 33 and the oil chamber R is formed by an internal oil passage L3 formed in the transmission case 2 and the internal oil passages L1, L of the support case 27 and the driven member 25.
2 and these oil passages are provided in the transmission case 2
By attaching and fixing to the support case 27 and attaching and fixing the hydraulic control valve 33 to the transmission case 2, it is configured to be connected and connected as it is, and the hydraulic pipe is omitted to simplify the structure. , To improve the workability of assembly.

As shown in FIG. 3, the hydraulic piston 28 of the PTO clutch 14 is actuated at a position where the drive side friction plate 35 faces the friction plate engagement portion of the inner engagement member 36 into which the spline is externally engaged. A small-diameter through hole 37 connected to the hydraulic chamber R is formed so that oil is smoothly supplied to the spline engagement portion, so that the movement of the friction plate 35 in the axial direction at the time of the clutch disengagement operation is smoothed. The clutch disengagement operation can be performed reliably. Although a part of the operating oil pressure is lost when the clutch is engaged, it has a small diameter and does not support the operation.

The hydraulic piston 28 has a spring 3
A brake mechanism B is provided that brakes the driven side when the clutch is slid to the clutch disengaged side by 0. That is,
A plurality of pins 38 driven and fixed to the hydraulic piston 28
Is provided so as to slidably pass through the drum portion 25a of the driven member 25, and a ring-shaped braking sliding contact member 39 (an example of a braking action portion) is screwed to the pin 38 on the outer side of the drum portion 25a. A ring-shaped stationary braking member 40 received and supported by the support case 27 is provided at a position where the sliding contact member 39 faces. As shown in FIG. 7, the fixed-side braking member 40 is configured such that a support pin 41 (an example of a transmission case-side fixed member) that is driven into and fixed to the support case 27 is engaged to prevent rotation. At the same time, the engagement recess 42 with which the support pin 41 is engaged
Is configured to allow relative rotation by a predetermined rotation angle (about 60 degrees). With this configuration, even in the clutch disengaged state, the switching operation of the PTO speed change mechanism 15 provided on the lower transmission side of the clutch can be performed.

That is, the support pin 41 and the engagement recess 4
2 moves the fixed side braking member 40 to the transmission case side.
With respect to the support pin 41 which is an example of the fixing member, the predetermined
Allow relative rotation by a rotation angle (about 60 degrees)
The rotation restricting means A is constituted.

The support case 27 of the clutch unit
Has a configuration in which a material is also used in a model in which the PTO clutch 14 is not mounted. That is, when the PTO clutch 14 is not mounted, the bearing 43 is simply supported, as shown in FIG. 4, and when the PTO clutch 14 is mounted, the driven member 25 is internally fitted from this material. The part and the mounting part of the brake mechanism B are cut out and machined.

In the claims, the reference numerals are used to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is an overall side view of an agricultural tractor.

FIG. 2 Transmission system diagram

FIG. 3 is a cross-sectional view of the PTO clutch in a state where the clutch is engaged.

FIG. 4 is a cross-sectional view when the PTO clutch is not mounted.

FIG. 5 is a sectional view of the PTO clutch in a clutch disengaged state.

FIG. 6 is a plan view showing a mounted state of a PTO clutch unit.

FIG. 7 is a front view showing a PTO clutch unit mounted state;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 5, 6 Power take-off shaft 14 Hydraulic clutch 15 Transmission mechanism 28 Hydraulic piston 39 Braking action part 40 Fixed side braking member 41 Transmission case side fixed member A Rotation restricting means B Brake mechanism

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60K 17/28 F16D 25/0638 F16D 67/04

Claims (3)

(57) [Claims] 1. A power take-out shaft (5), via a friction type hydraulic clutch (14), which is urged to the clutch disengagement side and is operated to enter the clutch by supplying hydraulic oil. (6) The transmission structure of an agricultural work vehicle having a transmission system configured to supply the hydraulic piston to the friction type hydraulic clutch (14). A braking mechanism (39) interlocked with (28) is provided with a brake mechanism (B) that presses against the fixed-side braking member (40) by a clutch-disengaging urging force to brake the fixed-side braking member (40) . The fixed braking member
The transmission case side fixing member (4 ) supporting the (40)
In contrast to 1), relative rotation is allowed only within a predetermined rotation angle range.
A transmission structure for an agricultural vehicle supported via a rotation restricting means (A) . 2. A power take-off shaft (5) through a friction type hydraulic clutch (14) which is urged to a clutch disengagement side and is operated to enter a clutch by supplying hydraulic oil. (6) A transmission structure of an agricultural work vehicle, wherein a transmission system is configured to supply the hydraulic clutch (14), and a transmission side of the hydraulic clutch (14) is provided with a gear shift type transmission mechanism (15). When the hydraulic piston (28) in 14) is operated to return to the clutch disengagement position, the braking action part (39) interlocked with the hydraulic piston (28) is pressed against the fixed-side braking member (40) by the clutch disengaging urging force. A brake mechanism (B) for braking, and the fixed-side brake member (40) is fixed to the fixed-side brake member.
The transmission case side fixing member (4 ) supporting the (40)
In contrast to 1), relative rotation is allowed only within a predetermined rotation angle range.
A transmission structure for an agricultural vehicle supported via a rotation restricting means (A) . 3. The transmission structure for an agricultural work vehicle according to claim 1, wherein the predetermined rotation angle range is about 60 degrees.