JP2003023808A - Link connection structure for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a link connection structure for a tractor, which is provided with lower link pins so as not to obstruct installation of a rear connection frame and a back hoe on a tractor body. SOLUTION: The rear connection frame 2 is installed at the rear of the tractor body T and a pair of the right and left lower link pins 16 are opposingly arranged at the right and left lower parts of the rear connection frame 2 at intervals 21 through which lower links 17 can be passed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor link connecting structure capable of connecting various rear working machines.

[0002]

2. Description of the Related Art A tractor is basically equipped with a connecting portion for mounting a rear working machine such as a rake device and a box blade device via a three-point link mechanism. The tractor is a tractor loader backhoe (TLB)
For example, Japanese Patent Laid-Open No. 2000-2654
It requires a rear connecting frame as a mounting device as disclosed in the '88 publication. The lower link pin, which is the connecting point at the front end of the lower link of the three-point link mechanism, is usually provided in a rear lower portion of the mission case or the brake case in a pair of left and right facing outward or inward.

[0003]

When the rear connecting frame of the TLB is mounted on the tractor vehicle body, if a lower link pin is provided on the tractor vehicle body side, it may interfere with the mounting of the rear connecting frame or the lower link frame. May become difficult to connect. Therefore, it is conceivable to provide the lower link pin at the lower part of the rear connecting frame, but if the lower link pin is provided outward at the lower part of the rear connecting frame, it may hinder the attachment of the rear connecting frame or the backhoe.

Further, it is necessary to provide a check chain connecting tool at a position separated from the lower link pin on the left and right, but there is also a problem that it is difficult to secure a mounting portion thereof. SUMMARY OF THE INVENTION It is an object of the present invention to provide a link connecting structure for a tractor which can solve the problems of the prior art. The present invention provides a tractor link connection structure in which lower link pins are arranged opposite to each other on the lower left and right sides of a rear connection frame so that the rear connection frame and the backhoe can be easily attached to a tractor vehicle body. The purpose is to

The present invention also provides a tractor link connecting structure in which the check chain connecting member can be easily and easily attached by providing the check chain connecting member across the left and right lower link pins. To aim.

[0006]

A first concrete means for solving the problems in the present invention is to provide a rear connecting frame 2 at the rear part of the tractor vehicle body T, and to the lower left and right parts of the rear connecting frame 2 there are lower links. That is, a pair of left and right lower link pins 16 are arranged to face each other with an interval 21 through which 17 can be inserted. As a result, the rear connecting frame 2 and the backhoe B can be easily attached to the tractor vehicle body T.

A second concrete means for solving the problem in the present invention is that, in addition to the first concrete means, a check chain connector 18 is provided across the left and right lower link pins 16. As a result, the check chain connector 18 can be attached using the left and right lower link pins 16, and the position of the left and right lower links 17 can be set. In addition to the second specific means, a third specific means for solving the problem in the present invention extends one of the left and right lower link pins 16 to the opposite side beyond the horizontal center of the tractor vehicle body T. The check chain connector 18 is pinned at the end of the extended pin.

As a result, the check chain connector 18 can be attached by using the left and right lower link pins 16, and the check chain connector 18 can be easily attached and detached. A fourth concrete means for solving the problems in the present invention is the concrete means according to any one of the first to third aspects, and the rear coupling frame 2 includes a pair of left and right vertical members 2A.
And an upper member 2B connecting the upper parts of the left and right vertical members 2A and a lower member 2C connecting the lower parts of the left and right vertical members 2A.

As a result, the rear connecting frame 2 can be firmly constructed. A fifth specific means for solving the problem in the present invention is that the top link bracket 15 is attached to the upper member 2B of the rear coupling frame 2 in addition to the fourth specific means. by this,
Only the rear connecting frame 2 can form two lower pivot points and one upper pivot point for connecting the three-point link mechanism. A sixth concrete means for solving the problem in the present invention is that, in addition to the fourth or fifth concrete means, the lower member 2C of the rear coupling frame 2 is formed by the hitch coupling body 14. .

As a result, not only the pivot points of the left and right lower links 17 but also the hitch connection points can be formed only by the rear connection frame 2. The seventh concrete means for solving the problems in the present invention is the concrete means according to any one of the first to sixth aspects, in addition to the vehicle body frame T1 which is long in the front-rear direction, the engine T2 and the mission case T3 are separated from each other in the front-rear direction. Is attached to form the tractor vehicle body T, and the rear connecting frame 2 is erected on the rear portion of the vehicle body frame T1. As a result, the tractor vehicle body T can be formed into a frame structure, and the rear connecting frame 2 can be provided on it.

An eighth concrete means for solving the problems in the present invention is that, in addition to any one of the first to seventh concrete means, a working machine lifting hydraulic device T10 is attached to an upper portion of the mission case T3. The hydraulic device T10 is connected to the upper part and / or the side part of the rear connecting frame 2. As a result, the rear connecting frame 2 can be firmly attached to the tractor vehicle body T. The ninth concrete means for solving the problems in the present invention is, in addition to any one of the first to eighth concrete means, supports a front axle case T6 at a front portion of the vehicle body frame T1 and connects it to a middle portion. The mast F1 of the front loader F is detachably supported, and the base frame B1 of the backhoe B is detachably connected to the rear connecting frame 2.

Thus, the rear connecting frame 2 can be used as a mounting device for the backhoe B of the tractor loader backhoe.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 9, reference numeral 1 denotes a tractor front loader backhoe (TLB), a front loader F is detachably mounted from a midway portion of a tractor vehicle body T to a front side, and a rear connecting frame 2 is provided at a rear portion of the tractor vehicle body T. A backhoe B, which is an example of a post-working machine, is detachably mounted via the intermediary of the tractor vehicle body T, and a midmount mower M can be mounted on a lower part of a middle portion of the tractor vehicle body T.

As shown in FIGS. 1 to 4, the tractor vehicle body T includes an engine T on a vehicle body frame T1 which is long in the front-rear direction.
2 and the mission case T3 are attached to each other so as to be spaced apart from each other in the front-rear direction to form a vehicle body T4, and a front axle case T6 for suspending a front wheel T5 is supported on a front portion of the vehicle body frame T1 and is supported from the mission case T3 to the left and right sides. A rear axle case T8 that suspends the rear wheel T7 is projected. The mission case T3
The working machine lifting hydraulic device T10 is attached to the upper part of the
A driver's seat device 4 in which the driver's seat 3 is reversible in the front and rear direction is mounted above the hydraulic device T10. This floor sheet T1
A fender T12 for the rear wheel T7 is attached to the left and right side portions of 1.

T13 is a bonnet that covers the engine T2, and the control section T14 is provided at the rear of the bonnet.
Further, at the front end of the body frame T1, the bonnet T13
A protector T15 is provided to protect the.
The body frame T1 is roughly divided into a main frame T
17 and left and right mast support frames T18 and left and right reinforcing frames T19. The main frame T1
Reference numeral 7 denotes a pair of left and right long plate members T17a which are attached by directly sandwiching the engine T2 and the transmission case T3.
And a large number of rod members in the front-rear direction that connect the left and right long plate members T17a to each other, and a horizontal member T17b made of a plate member, which are formed in a substantially rectangular shape in a plan view.

At the lower front end of the main frame T17, there is provided a supporting portion T21 for supporting the front axle case T6 so as to be swingable around the center pin, and an elevating device for supporting the mid mount mower M from the middle to the rear. Is formed. Left and right mast support frames T1
Reference numeral 8 denotes a lateral tension member T18a fixed to the left and right outer surfaces of the main frame T17 in the front-rear direction midsection so as to project outward.
And a mast support member T18b which is erected on the upper surface of the outer end of the lateral tension member T18a. The mounting portion of the lateral tension member T18a is detachably bolted to the outer surface of the main frame T17. .

In each of the left and right reinforcing frames T19, the two strips T19a and T19b are shifted forward and backward so as to be laminated in an overlapping state at a midway portion, and the front end of the front strip T19a is fixed to the horizontal member T18a by a bracket T19c. The rear strip T19b is connected to the rear surface of the long strip T17a of the main frame T17 via a connecting member such as a bolt. The rear strip T19b and the long strip T1 are connected to each other.
It faces 7a with a gap. The reinforcing frame T19 is arranged substantially overlapping the main frame T17 in a side view, and the mast support member T1.
The load applied to 8b can be distributed to the rear part of the mainframe T17.

Similar to the horizontal member T17b, reference numerals 6 and 7 denote front and rear mounting tools for connecting the left and right long plate members T17a to each other so that the distance between them can be adjusted, and also serve to mount the mission case T3 to the main frame T17. . Front fitting 6
Has a pair of left and right mounting bodies 6L and 6R in a front view,
The vertical portions of the left and right mounted bodies 6L and 6R are long plate materials T17a.
Bolted to the inner surface of the mission case T
3 is bolted. The left and right mounted bodies 6L and 6R
The horizontal parts of are connected to each other, and the left and right long plate materials T1
The connection length can be finely adjusted to match the 7a interval. The lower portion (horizontal portion) of the front mounting device 6 projects downward from the main frame T17 and protects the lower front portion of the mission case T3.

Similar to the front mounting tool 6, the rear mounting tool 7 connects the vertical parts of the left and right mounting bodies 7L and 7R to the long plate material T17a and the mission case T3, and connects the horizontal parts to each other to form the left and right long plate materials. It is adapted to the T17a interval. The front loader F pivotally supports the base portion of the boom F2 on the upper part of the left and right masts F1 so as to swing up and down, pivotally supports the bucket F3 at the tip of the boom F2 for scooping and dumping, and the boom F2 by a boom cylinder F4. The bucket cylinder F5 can hydraulically drive the bucket F3.

The mast F1 is a mast support frame T.
It is configured to be fitted into the mast support member T18b of 18 from the upper side and to lock the lower part, and to lock the middle part with the lock pin F6. When not in use, the front loader F can be disengaged from the mast support frame T18 by pulling out the lock pin F6. However, when only the backhoe work or the mower work is performed for a long period of time, the body frame T1 becomes the main frame. The left and right mast support frames T18 and the reinforcing frame T19 may be separated from T17.

The mid-mount mower M is mounted on the lower part of the abdomen of the vehicle body T4 via suspension means M1 so as to be able to move up and down, and is configured so that power is transmitted from the mission case T3 to rotate the blade. There is. This mid-mount mower M can be detached together with the suspension means M1 from the tractor body T when carrying out loader work and / or backhoe work. The backhoe B is a base frame B as shown in FIGS.
1 has a pair of left and right mounting bodies B2, a swing bracket B3 is pivotally supported on the rear part of the base frame B1 so as to swing around a vertical axis B12, and a control part B4 is mounted on the upper part of the base frame B1. It is equipped with a hydraulically driven stabilizer (outrigger) T16 on the left and right of the base frame B1.

The swing bracket B3 is swingable right and left by one swing cylinder B5. The base of the boom B6 is pivotally supported on the swing bracket B3.
The boom cylinder B7 is allowed to swing vertically, the arm B8 is pivotally supported at the tip of the boom B6 and the arm cylinder B9 is vertically swingable, and the bucket B10 is pivotally supported at the tip of the arm B8 and scooped by the bucket cylinder B11.・ The dump operation is free. The base frame B1 includes two flat plates B1a and B1b arranged at a vertical interval and a plate member B16b that forms a mounting portion T16a of the stabilizer T16.
B16c and a pair of left and right mounting bodies B2 and the like are connected to each other to form an internal cavity, and there are a pair of upper and lower bearing portions B1c for supporting the vertical axis B12, and the vertical axis B12 also has a short axis separated vertically. They are arranged concentrically.

Therefore, the bearing portion B3 of the swing bracket B3
Also, a has a bifurcated shape, and a connecting protrusion B3b to which the tip of the cylinder rod B5a of the swing cylinder B5 is connected protrudes laterally from a vertical middle portion of the side surface of the swing bracket B3. A cylinder mounting portion B19 that pivotally supports the base portion of the swing cylinder B5 with a pin B5b is arranged on one of the left and right sides of the base frame B1, that is, on the right side in the embodiment, is near the mounting portion T16a of the right stabilizer T16, and is mounted on the right side. It is near the body B2 and is located between them.

That is, the cylinder mounting portion B19 is fixed to the plate material B16c and the mounting body B2 between the upper and lower flat plates B1a and B1b constituting the base frame B1. The single swing cylinder B5 is a clevis type that swings the swing bracket B3 left and right by a required angle, and the swing angle is smaller than that of the trunnion type.
Only two hydraulic hoses are connected, their bulges are small, and the required space is reduced. Since the swing cylinder B5 has a base portion on one of the left and right outer portions with respect to the base frame B1 and a tip end of the cylinder rod B5a on the center side, the swing cylinder B5 should be inclined with respect to the front-back direction of the base frame B1. In comparison with the case where two trunnions are arranged in parallel with the front-rear direction, they can be arranged without being limited to the space in the central portion in the left-right direction of the base frame B1, and conversely the front-rear dimension of the base frame B1. Can be reduced, and the front and rear dimensions of the backhoe B can be shortened so that the backhoe B can be arranged closer to the tractor vehicle body T.

The mounting portion B19 of the swing cylinder B5 is located near the left and right upper and lower engaging portions 14 and 15, near the mounting portion B16a of the stabilizer B16, or the upper and lower engaging portions 14 and 15 and the stabilizer B16. Since it is arranged between the portion B16a and the portion B16a, the swing cylinder B5 is supported at the position of highest strength in the base frame B1. A step B24 is attached to the upper surface of the base frame B1 via a support rib B23, and the control section B4 is mounted on the step B24.

Left and right mounting bodies B2 of the backhoe B
Is provided with upper and lower engaging portions B14 and B15, and the upper and lower engaging portions B14 and B15 are detachably connected to the left and right upper and lower connecting portions 11 and 12 of the rear connecting frame 2, respectively, with respect to the tractor vehicle body T. Backhoe B can be attached and detached. 1 to 7, the upper coupling portion 11 of the rear coupling frame 2 has a pin 11a, and the mounting body B2
The upper engaging portion B14 of the pin 11a is open to the front.
The concave portion B14a that fits (avoids interference) with the concave portion B1.
The mounting means B20 holds the pin 11a with the pin 4a fitted to the pin 11a.

The mounting means B20 includes upper and lower pins B2.
0a, a pair of upper and lower mount holders B20b pivotally supported on the upper part of the mounting body B2, and a spring B20c for urging the upper and lower mount holders B20b in the expanding direction.
And a holding member B20d that holds the state when the upper and lower mount holders B20b are closed, and the mount holder B20b is formed with a holding portion B20e that holds the pin 11a. The lower connecting portion 12 of the rear connecting frame 2 has a concave portion 12a that is open upward, and the lower engaging portion B15 of the mounting body B2 is a long rod B15a extending right and left.
The rod B15a is inserted into the recess 12a from above and received.

To mount the backhoe B on the tractor vehicle body T, the base frame B1 is slightly rearward and downward, and the rod B15a of the lower engaging portion B15 of the mounting body B2 is mounted.
The tractor vehicle body T is moved so that the concave portion 12a of the lower connecting portion 12 is located below the rod, and then the stabilizer T16 is operated to keep the base frame B1 in a horizontal posture and the rod B.
15a is inserted into the recess 12a. The rod B15
a is received by the recess 12a, the mounting means B2
When 0 approaches the pin 11a, the mount holder B2
The back side of the holding portion B20e of 0b contacts the pin 11a, and resists the spring B20c, and the upper and lower mount holders B20b.
Acts to close.

When the upper and lower mount holders B20b are closed and the holding portion B20e is fitted to the pin 11a, the holding member B20d is inserted between the upper and lower mount holders B20b by the elastic spring B20f to hold the pin 11a. The holding member B20d is urged toward the mount holder B20b by an elastic spring B20f. By separating the holding member B20d from between the upper and lower mount holders B20b against the elastic spring B20f,
The mounting means B20 is opened, and the backhoe B can be separated from the tractor body T.

Since the holding member B20d is slanted rearward and downward and is made to go under the step B24, the front-back dimension of the base frame B1 can be shortened, and the step B24 is arranged closer to the tractor body T. it can. The rear connecting frame 2 is connected to the main frame T17 at an intermediate portion in the vertical direction, and the upper and intermediate portions are connected to the hydraulic device T.
The rear vertical frame 13 is attached to the upper part of the transmission 10, and the hitch connecting body 14 is provided on the lower part thereof so that it can be detachably attached to the rear part of the body frame T1 so as to surround the back part of the mission case T3. It is erected.

The rear connecting frame 2 not only has a function of mounting the backhoe B and the rear vertical frame 13, but can also be equipped with a rake device, a box blade device, a rotary tiller, a crusher, a trailer, etc. as a rear working machine. These devices can be used alone or in combination with the front loader F, the mid mount mower M, etc. mounted on the tractor body T to perform various operations. 5 to 11, the rear connecting frame 2 includes a pair of left and right vertical members 2A, an upper member 2B connecting the upper portions of the left and right vertical members 2A, and a lower member 2C connecting the lower portions of the left and right vertical members 2A.
Have and.

Each of the left and right vertical members 2A has a lower member 2Aa whose upper portion and lower portion are bent horizontally in opposite directions, and the lower member 2A.
Similarly, an upper member 2Ab whose upper portion and lower portion are bent in opposite horizontal directions is fixed to the upper portion of a. On the outer surface of the lower member 2Aa of the vertical member 2A, a long plate member T17a of the main frame T17 is provided at an intermediate portion in the vertical direction, a member forming the upper connecting portion 11 at the upper portion, and a member forming the lower connecting portion 12 at the lower portion. Each is fixed. The lower member 2C is bolted to the lower horizontal portion of the left and right lower members 2Aa. The lower member 2C may be formed of a simple plate, but in the embodiment, the hitch connection body 14 is used, and the compression device is a hitch joint 14a that serves as a hitch connection point.
A tow rod such as a trailer can be connected.

Lower link pins 16L and 16R are provided below the left and right vertical members 2A. Both lower link pins 1
A flange 16a is welded to 6L and 16R, and the flange 16a is bolted to the inner surface of the vertical member 2A. The left and right lower link pins 16L and 16R are arranged inwardly facing each other with a space 21 through which the lower link 17 can be inserted. The right lower link pin 16R (or the left lower link pin 16L may be used) is extended to the opposite side (left side) beyond the lateral center of the tractor vehicle body T.

Reference numeral 18 denotes a check chain connecting member 18 which is fitted and supported across the left and right lower link pins 16, and is fixed to the right lower link pin 16R by a stop pin 18a at the substantially right and left center of the tractor vehicle body T. The chain connecting tool 18 can be attached and detached only by inserting and removing one stop pin 18a. The check chain connector 18 hooks the front end of a check chain 22 that is erected between the left and right lower links 17, and moves left and right while the front ends of the left and right lower links 17 are fitted to the left and right lower link pins 16. It also has the function of restricting movement, and does not require a special lower link retaining member.

That is, the width of the portion of the check chain connector 18 that fits into the lower link pin 16 is set so as to substantially fill the space between the left and right lower links 17 fitted into the left and right lower link pins 16. The left and right lower links 17 can be removed from the space (gap) 21 only by detaching the check chain connecting tool 18. Lower link 1
7 is a hole for inserting a pin that connects the lift rod, and the lift rod is a lift arm T of the hydraulic device T10.
10a is connected. An upper member 2B is connected to the upper member 2Ab of the vertical member 2A via a bracket, and a top link bracket 15 pivotally supporting the top link 24 via a pin is fixed to the upper member 2B.

The top link bracket 15 has a plate connecting portion 15a and a rear connecting link connecting portion 15a.
The upper part of the mounting portion 15a is fixed to the upper member 2B, and the lower end thereof is bolted to the hydraulic device T10. Also, the upper member 2A of the vertical member 2A
The lower substrate 13A of the rear vertical frame 13 is bolted to the upper horizontal portion of b. The rear vertical frame 13 is the lower substrate 13A.
The lower end of the frame body 13B, which is formed by bending a pipe into a substantially inverted U-shape, is fixed to the upper part, and the lower member 13C connected to the lower ends of the frame body 13B is mounted on the lower substrate 13A. The main body 13B bulges outward from the lower part to the left and right from the middle part to the upper part, and can be bent back and forth at the middle part.

The lower substrate 13A reinforces the upper portion of the rear connecting frame 2, and the upper member 2B reinforces the lower portion of the rear vertical frame 13. A pair of left and right mounting reinforcement members 23 shown in FIG.
Connects the left and right vertical members 2A and the hydraulic device T10,
The mounting strength of the rear connecting frame 2 to the tractor vehicle body T is improved. Further, in FIG. 8, reference numeral 25 denotes a PTO shaft that projects rearward from the mission case T3.

The present invention is not limited to the above embodiment, but can be variously modified. For example,
The length of the right lower link pin 16R is changed to the left lower link pin 16
It is also possible to make the distance 21 sufficiently wide by making it the same as L, and in that case, the check chain connector 18 provided across the left and right lower link pins 16 is pinned to the left and right lower link pins 16 at two points on the left and right. To do. Also, the number of post-working machines is 3
Although it is mounted using the point link mechanism, it may be a post-working machine mounted using the two point link mechanism.

[0039]

According to the present invention described in detail above, the lower link pins 16 on the lower left and right sides of the rear connecting frame 2 are arranged to face each other, and the rear connecting frame 2 is attached to the tractor vehicle body T and the backhoe B is attached. There is no hindrance to the attachment, and there is a space 21 between the left and right lower link pins 16, and the lower link 17 can be inserted from the space 21 and fitted into the lower link pin 16. Further, the check chain connector 18 can be attached using the left and right lower link pins 16, and the position of the left and right lower links 17 can be set.

[Brief description of drawings]

FIG. 1 is an overall side view showing an embodiment of the present invention.

FIG. 2 is a plan view showing the frame structure.

FIG. 3 is a partially exploded side view showing the frame structure.

FIG. 4 is a side view showing a rear part of the tractor and a backhoe.

FIG. 5 is a side view of the rear connecting frame and the front part of the backhoe in a separated state.

FIG. 6 is a side view showing a connected state of the rear connecting frame and the front part of the backhoe.

FIG. 7 is a plan view showing a rear part of the tractor and a backhoe.

FIG. 8 is a rear view of the tractor equipped with the rear connecting frame.

FIG. 9 is a rear view of the rear connecting frame.

FIG. 10 is a partial cross-sectional plan view in which a lower link is connected to a rear connecting frame.

FIG. 11 is an exploded plan view of the lower link connecting structure.

[Explanation of symbols]

1 tractor, front loader, backhoe 2 Rear connection frame 11 Upper connection 12 Lower connection part 14 Hitch connection 15 Top link bracket 16 Lower link pin 17 Lower Link 18 Check chain connector 21 Interval (gap) 22 check chain T tractor T1 body frame T3 mission case T4 body T10 hydraulic system T17 mainframe F front loader M mid mount mower B backhoe B1 base frame B3 swing bracket F front loader

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Oshima             64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubo Co., Ltd.             Ta Sakai Factory (72) Inventor Sakuya Harada             64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubo Co., Ltd.             Ta Sakai Factory (72) Inventor Yoshio Toyama             64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubo Co., Ltd.             Ta Sakai Factory (72) Inventor Hiroshi Kawabata             64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubo Co., Ltd.             Ta Sakai Factory F term (reference) 2B041 AA09 AB05 AC01 CA03 CA16                       CC14 CC16

Claims (9)

[Claims] 1. A rear connecting frame is provided at a rear portion of a tractor vehicle body, and a pair of left and right lower link pins are arranged in opposed relation to each other at lower left and right portions of the rear connecting frame with an interval into which a lower link can be inserted. A link connecting structure for a tractor, which is characterized in that 2. The link connecting structure for a tractor according to claim 1, wherein a check chain connecting tool is provided across the left and right lower link pins. 3. One of the left and right lower link pins is extended to the opposite side beyond the left and right center of the tractor vehicle body, and the check chain connecting tool is pinned by the extended pin end portion. Item 2. A link connecting structure for a tractor according to Item 2. 4. The rear connecting frame has a pair of left and right vertical members, an upper member connecting upper parts of the left and right vertical members, and a lower member connecting lower parts of the left and right vertical members. The link connection structure for the tractor according to any one of 1 to 3. 5. The tractor link connection structure according to claim 4, wherein a top link bracket is attached to an upper member of the rear connection frame. 6. The tractor link connection structure according to claim 4, wherein the lower member of the rear connection frame is formed of a hitch connection body. 7. A tractor vehicle body is constructed by mounting an engine and a transmission case on a vehicle body frame long in the front-rear direction so as to be spaced apart from each other in the front-rear direction, and the rear connecting frame is erected on a rear portion of the vehicle body frame. The link connection structure for a tractor according to any one of claims 1 to 6, which is characterized in that. 8. A hydraulic device for raising and lowering a working machine is attached to an upper portion of the mission case, and the hydraulic device and the upper portion and / or side portion of the rear connecting frame are connected to each other. The link connection structure for the tractor according to any one of 1. 9. A front axle case is supported at a front portion of the vehicle body frame, a mast of a front loader is detachably supported at a middle portion thereof, and a base frame of a backhoe is detachably coupled to a rear coupling frame. Claims 1 to 1 characterized in that
8. The tractor link connection structure according to any one of 8.