JP3401438B2 - Tractor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relatively small tractor constructed in consideration of versatility.

[0002]

2. Description of the Related Art As a vehicle body structure of a tractor, for example, as disclosed in Japanese Patent Laid-Open No. 7-329663,
An engine, a main clutch housing, a hollow housing, and a monobody type in which a transmission case is connected in series are often used, and in some tractors,
For example, Japanese Utility Model Laid-Open No. 61-110428 and Japanese Patent Laid-Open No. 3-1
As disclosed in Japanese Patent No. 43775, a frame-mounted type is also used in which an engine is mounted and supported on the front parts of a pair of left and right main frames, and a mission case is connected to the rear parts of the main frames.

In a tractor, a fall protection frame may be provided upright on the rear part of the vehicle body (see Japanese Patent Laid-Open No. 7-329663) or a towing type working device may be connected. Since the structure is a mission case, the base end of the fall protection frame and the bracket for connecting the working device were connected to the mission case. Therefore, the mission case has been set to be considerably robust considering not only the strength required for the vehicle body structure but also the strength against the load received from the attached device. In addition, since the mission case of the tractor is generally equipped with a hydraulically-driven lift arm that moves up and down the work device, strength against the work device lifting load is also required, and the mission case is made of cast iron. Things were being used.

[0004]

However, the cast iron mission case generally has a large weight, and in order to secure necessary strength, the mission case of the tractor is increased in order to increase the wall thickness and to provide a large number of reinforcing ribs. The mission case deployed at the rear becomes considerably heavy, the weight of the entire vehicle body increases, and the weight balance of the vehicle body is shifted to the rear, and it becomes necessary to attach a large balance weight to the front part of the vehicle body. This tends to result in increased weight.

The present invention has been made by paying attention to such a point, and by improving the vehicle body structure, the required strength can be secured, while the mission case is made thin and lightweight, or The main purpose is to enable aluminum die casting and reduce the weight of the vehicle body.

[0006]

[Means for Solving the Problems] [Structure, Action and Effect of the Invention According to Claim 1]

(Structure) In the tractor of the invention according to claim 1, a pair of left and right main frames formed by arranging long plate members in a front-rear direction in a vertical posture are arranged to face each other with a predetermined left-right interval, and their front end portions are arranged to each other. It is connected by a horizontal frame, the engine is mounted and supported on the front parts of the left and right main frames, and the mission case is connected and supported by the rear part of the main frame by placing it between the left and right main frames. axle
The front wheel is supported through the case, and the mission
The rear wheel is axially supported by the casing, and the rear end of the main frame is extended to the rear of the rear wheel axis.

(Operation) According to the above construction, by connecting the attachment devices to the rear end of the main frame extending rearward from the rear axle, the load from these attachment devices is not directly applied to the mission case. It can be supported by a frame. As a result, the load on the mission case is reduced, and the required strength of the mission case is correspondingly reduced, and even if it is made of cast iron, the wall thickness is reduced and the reinforcing ribs are reduced, etc. The weight of the mission case can be reduced, and if the mission case is made of die-cast aluminum, the weight of the mission case can be further reduced.

(Effect) Therefore, according to the first aspect of the invention, the main frame can share and support the load of the attachment device, so that the weight of the mission case can be reduced while ensuring the strength required for the vehicle body. This makes it possible to reduce the weight of the entire vehicle body. In addition, the weight reduction of the transmission case at the rear of the vehicle body is effective for balancing the front and rear weight of the vehicle body as a whole, and the balance weight at the front portion of the vehicle body is reduced to further contribute to the weight reduction of the vehicle body.

[Structure, Action and Effect of the Invention According to Claim 2]

(Structure) A tractor according to a second aspect of the present invention is the tractor according to the first aspect of the present invention, in which a base end of a fall protection frame is connected to and supported by a rear end portion of the main frame.

(Operation / Effect) According to the above configuration, the base end of the fall protection frame can be firmly supported by the main frame, and the function of the fall protection frame can be enhanced.

[Structure, Action and Effect of the Invention According to Claim 3]

(Structure) A tractor according to a third aspect of the present invention is the tractor according to the first or second aspect, wherein the main frame is provided with a mid mount type mower connecting portion and a hunt loader connecting portion.

(Operation) According to the above structure, the heavy load of the front loader such as the mower or the loader work load can be directly received by the main frame having high strength. In this case, since the heavy load is supported by the main frame made of the plate material in the vertical posture, it is possible to cope with a sufficiently large load even if the plate thickness is small. Further, since the load in the front-rear direction generated during the loader work also acts as a load along the plate surface of the main frame, the main frame sufficiently opposes this.

(Effect) Therefore, according to the invention of claim 3, the weight of the mower or the front loader can be reduced while the weight of the vehicle body can be suppressed by using the main frame of the plate material having a relatively thin thickness. It is possible to satisfactorily carry out heavy work while ensuring sufficient strength to withstand loads and work loads.

[Structure, Action and Effect of the Invention According to Claim 4]

(Structure) A tractor according to a fourth aspect of the present invention is the tractor according to the third aspect, wherein a transmission shaft for transmitting power from the transmission case to the front axle case is laterally provided between the left and right plate frames. The input case projecting on the upper surface of the deck of the mid-mount type mower is displaced in the direction opposite to the direction in which the transmission shaft is eccentrically arranged, and the mower is mounted on the lower abdomen of the machine body.

(Operation) According to the above structure, a transmission shaft for transmitting power from the transmission case to the front axle case,
The input case protruding from the upper surface of the deck of the mid-mount type mower is unevenly distributed between the left and right plate frames on the left and right without interfering with each other. As a result, the space above the input case can be secured, the mower can be raised significantly, and the maximum ground height of the mower can be sufficiently secured.

(Effect) Therefore, according to the invention as claimed in claim 4, even when overcoming a ridge on the ground, the mower on the lower abdomen of the fuselage does not get in the way, and a smooth work site is smoothed. It becomes possible to drive to.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the entire side surface of a tractor according to the present invention. This tractor has a vehicle body structure in which an engine 2 is mounted and supported on the front parts of a pair of left and right main frames 1 which are long in the front-rear direction, and a mission case 3 made of aluminum die casting is connected to the rear part of the main frame 1, and The front axle case 4 is located below the front of the main frame 1.
The left and right front wheels 5 are rotatably supported by the vehicle, and the rear wheels 6 as main propulsion wheels are rotatably supported on the left and right of the mission case 3 in a four-wheel drive structure.

As shown in FIGS. 7 and 8, the left and right main frames 1 are formed by arranging long straight thick plate members in a vertical posture in the front-rear direction. The front end of the frame 1 is connected by a horizontal frame 7, and a pair of front and rear brackets 8 and 9 for supporting the front axle case 4 in a freely rolling manner are provided at the lower part on the front end side.
Is installed over the left and right main frames 1, and further, a plate stay 10 that is bent in a V shape is installed over the left and right main frames 1 at an intermediate portion in the front-rear direction.
A pair of left and right engine mounting portions 11a and 11b are attached to the front and rear of the front portion of the main frame 1, and the engine 2 is mounted and supported here via a vibration damping rubber 12 in a four-point vibration-proof support state. ing.

The main frame 1 extends beyond the axis of the rear wheel 6 and extends rearward of the mission case 3, and is connected to the extending portion 1a to extend left and right. The upper and lower ends of the vertical frame 13 are connected to the left and right lower ends of an arch-shaped tipping protection frame 15 which stands upright behind the driver's seat 14. The rear wheel fender portion 17 connected to the driving step 16 is jointly fastened between the upper end of the vertical frame 13 and the left and right lower ends of the overturn protection frame 15.

The mission case 3 is inserted between the left and right main frames 1 and bolted from the side.
When the bolt connection is released, the mission case 3 can be inserted into and removed from the main frame 1 from above or from the rear. And this mission case 3
A hydraulic continuously variable transmission (HST) 19 is connected to the front surface of the engine, and the engine output is input to the hydraulic continuously variable transmission 19 via the transmission shaft 20.
The gear shift output is transmitted to the mission case 3.

The internal structure of the mission case 3 is shown in FIG.
And shown in FIG. That is, the output shaft (motor shaft) 21 of the hydraulic continuously variable transmission 19 is connected to the traveling system input shaft 22 of the mission case 3, and the forward or reverse speed change power transmitted to the input shaft 22 is changed to the gear change speed. Mechanism 2
The speed of the bevel pinion shaft 24 is further reduced by 3 and further transmitted to the bevel pinion shaft 24, and the output of the bevel pinion shaft 24 is greatly reduced by the bevel gear mechanism 25 and transmitted to the differential mechanism 26. Rear wheels 6 that extend left and right as rear axles 27 and are connected to the respective rear axles 27
Are being driven. Also, each rear axle 27
Is configured to be able to be respectively braked by a multi-plate type side brake 28, and the differential mechanism 26 is provided with a differential lock mechanism 29.

The power of the bevel pinion shaft 24 is transmitted to the front wheel drive shaft 32 via the intermediate shaft 31, and the power extracted from the front wheel drive shaft 32 is transmitted to the transmission shafts 33, 3.
4 and the universal joint 35 to the input shaft 36 of the front axle case 4 so that the left and right front wheels 5 are rear wheels 6.
It is designed to be driven at a speed synchronized with. Here, the transmission shafts 33, 34 are arranged so as to be displaced to the right between the left and right main frames 1, and the input shaft 36 is also displaced to the right with respect to the rolling fulcrum a of the front axle case 4. It has been installed at the designated position.

Further, the pump shaft 41 of the hydraulic continuously variable transmission 13 is extended rearward and connected to the PTO system transmission shaft 42 of the transmission case 3, and the power input to this transmission shaft 42 is a multi-plate hydraulic type. Is transmitted to the output gear 44 via the PTO clutch 43, and the power of the output gear 44 is selectively transmitted to the rear PTO shaft 46 and the mid PTO shaft 47 via the shift gear 45. In detail,
When the shift gear 45 is shifted to the middle of the shift range as shown in FIG. 5, the shift gear 45 moves to the intermediate shaft 48.
And the gear 49 that is loosely fitted to this
The rear PTO shaft 46 and the mid PTO shaft 47 are both driven, and the shift gear 45 is shifted rearward to move the intermediate shaft 4
Only the rear PTO shaft 46 can be driven by occlusively connecting only to the gear 8, and the shift gear 45 can be shifted forward so that only the gear 49 can be occlusally connected.
It is configured so that only the TO shaft 47 can be driven.

Further, a cast iron cylinder case 49 is connected to the upper portion of the transmission case 3 having the above-described structure, and a pair of left and right lift arms 51 driven and rocked by an internal hydraulic cylinder 50 are provided. Various working devices connected via a three-point link mechanism (not shown) can be moved up and down.

A mid-mount type mower M is supported between the front wheel 5 and the rear wheel 6 via a front link 55 and a rear link 56 so as to be vertically movable. That is, the single-acting hydraulic cylinder 57 is provided between the left and right main frames 1, and the hydraulic cylinder 5 is provided outside the left and right main frames 1.
A pair of left and right lift arms 58 that are driven and swung around the fulcrum b by 7 are provided. The lift arms 58 and the rear link 56 are suspended and connected via a suspension link 59, and the hydraulic cylinder 57 is extended by the extension operation. The mower M is driven up and the mower M is lowered by its own weight by the shortening operation of the hydraulic cylinder 57.

As shown in FIG. 2, the mower M is constructed by arranging three blades 61C, 61L and 61R which are vertically driven inside a deck 60 which is opened downward in parallel. , The rear-facing input shaft 63 of the input case 62 installed on the deck 60, and the mid-PTO shaft 47
And are linked and coupled via a transmission shaft 64 and a universal joint 65.

The input case 62 includes a central blade 61.
The central blade 61C is arranged immediately above C and is orthogonally interlocked by a bevel gear in which the rotating shaft 66C of the central blade 61C and the input shaft 63 are internally mounted, and the central blade 61C is rotationally driven clockwise in plan view, and the central blade is also rotated. Rotating shaft 66C
And left and right blades 61L and 61R rotating shafts 66L and 66R
And are interlocked via a belt 67, the left and right blades 61L and 61R are also rotationally driven in the same direction as the central blade 61C, and the grass mowed by these blades 61C, 61L and 61R is placed on the blade rotation wind. It is configured such that wind power is conveyed to the right side of the deck and is discharged to the outside from a discharge port 68 formed at the right end of the deck.

Here, the mower M is constructed such that the input case 62 enters between the left and right main frames 1 when the mower M is fully raised, and the input case 62 interferes with the transmission shaft 33 to the front wheels 5. Therefore, the entire mower M is mounted on the left side of the center of the vehicle body.

Further, the mower M is constructed so as to be maintained at an arbitrary cutting height without touching the ground and to perform a cutting operation, and is provided with means for setting the lowered position thereof in multiple stages. That is, as shown in FIGS. 9 and 10, the fulcrum shaft 70 penetratingly provided across the left and right main frames 1 and the hydraulic cylinder 57 are interlockingly connected via the interlocking arm 71. The lift arms 58 are respectively connected to the end portions of the interlocking arms 7.
When the regulating arm 72 protruding from the boss portion of 1 contacts the stopper member 73 provided on the left main frame 1 from below, the downward swing of the lift arm 58 is regulated to contact. It has become.

The stopper member 73 is rotatably mounted on a bracket 74 provided on the inner side of the left main frame 1 so as to be rotatable about an oblique vertical axis c, and is rotatable and adjustable by an operating shaft 75 with a knob. Has become. In addition, the outer peripheral surface 73a of the upper half of the stopper member 73 is formed in a polygonal shape, and the leaf spring 76 that presses the polygonal outer peripheral surface 73a is attached to the bracket 74 in a cantilevered manner. Since the leaf spring 76 is in stable contact with one flat surface of the outer peripheral surface 73a, the stopper member 73 can be stably held at a plurality of rotational positions corresponding to the number of corners of the polygon.

The lower end of the lower half portion of the stopper member 73 is formed in a stepped shape in the circumferential direction, and the regulating arm 7
By setting the height of the step portion facing 2 in accordance with the rotation of the stopper member 73, the downward swing limit of the lift arm 58 can be adjusted to a plurality of steps, and thus the lowermost height of the mower M can be adjusted. That is, it is possible to adjust and set the cutting height in multiple stages.

As shown in FIGS. 7 and 11, on the front side surfaces of the left and right main frames 1, a connecting portion 80 for connecting a support bracket 79 for connecting the base column 78 of the front loader L with a bolt is provided in advance. Therefore, it is possible to connect the front loader L as necessary to perform scooping and loading work of soil and sand, or loading work of cut grass and agricultural products.

[Brief description of drawings]

FIG. 1 is an overall side view of a tractor according to the present invention including a mid mount type mower.

FIG. 2 is an overall plan view showing a lower structure of a tractor.

FIG. 3 is a rear view of the rear portion of the fuselage with a partial cutaway

FIG. 4 is a rear view showing the front wheel support structure.

[Fig. 5] Side view of the mission case in vertical section

FIG. 6 is a vertical cross-sectional rear view showing a part of the mission case.

FIG. 7 is a side view of the main frame.

FIG. 8 is a plan view of the main frame.

FIG. 9 is a side view of the mower height setting means.

FIG. 10 is a plan view thereof.

FIG. 11 is a side view of the front part of the fuselage with a front loader attached.

[Explanation of symbols]

1 Main Frame 2 Engine 3 Mission Case 5 Front Wheel 4 Front Axle Case 6 Rear Wheel 7 Side Frame 15 Fall Protection Frame 33 Transmission Shaft 62 Input Case M Moore L Fronter

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP 10-7016 (JP, A) JP 7-329663 (JP, A) JP 7-96865 (JP, A) Actual development 56- 53622 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62D 49/00 B62D 21/10 B62D 25/08

Claims (4)

(57) [Claims] 1. A pair of left and right main frames, each of which is formed by arranging long plate members in a front-rear direction in a vertical posture, are arranged to face each other at a predetermined left-right interval, and front end portions thereof are connected by a horizontal frame. The engine is mounted and supported on the front part, and it is positioned between the left and right main frames to connect and support the mission case to the rear part of the main frame.
Support the front wheels under the front part of the chassis via the front axle case
At the same time, support the rear wheels on the mission case,
One, tractor, characterized in that are extending the rear end of the main frame to the rear of the rear wheel axis. 2. The tractor according to claim 1, wherein a base end of a fall protection frame is connected and supported to a rear end portion of the main frame. 3. The tractor according to claim 1, wherein the main frame is provided with a support portion of a mid-mount type mower and a support portion of a hunt loader. 4. A transmission shaft for transmitting power from the mission case to the front axle case is laterally offset between the left and right main frames, and is provided on the upper surface of the deck of a mid-mount type mower. The input case
The tractor according to claim 3, wherein the mower is mounted on the lower abdomen of the machine body by displacing the transmission shaft in a direction opposite to the eccentric direction of the transmission shaft.