JPS6124010Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a draft cam support adjustment device for a tractor hydraulic system with draft control, which allows the draft cam to be adjusted without being affected by the feedback link or without affecting the link. The purpose is to enable easy adjustment of draft links from outside.

As is well known, when a tillage work machine such as a plow is attached to a tractor by a three-point linkage, a hydraulic system with draft control is employed to maintain a constant traction force.

This draft control basically senses the displacement of the load spring and feeds it back to the hydraulic control valve via the draft cam.
As the load spring, there are methods such as interposing a U-shaped leaf spring at the top link attachment part of the three-point link, means using a torsion bar, and means using a torsion bar at the lower link attachment part of the three-point link. It is common practice to sense this and provide feedback electrically or mechanically.

Electrical means are less accurate in their responsiveness than mechanical means, and mechanical means are preferred in terms of accuracy.

Regardless of the type, it is important to set the relative position between the draft cam and the draft link, and even if the setting is accurate when assembled, deviations may occur with use, so adjusting the relative position is important. It has important meaning.

In view of the above-mentioned circumstances, the present invention has been developed to particularly improve the draft cam support device to enable independent adjustment of only this device, as well as external adjustment. Describe.

In FIGS. 1 to 3, 1 is a tractor body, a transmission case 2 is a structure, and 3 is a wheel. Mission case 2
has a built-in differential device 4, and the vehicle body 1
A PTO transmission 5 is built into the rear side of the vehicle and drives an axle 6 and a PTO shaft 7, respectively.

A hydraulic device 8 is mounted on the rear upper surface of the vehicle body 1, and the hydraulic device 8 has a hydraulic housing 9, a hydraulic cylinder device 8A consisting of a cylinder, a piston, a piston rod, etc. housed in the hydraulic housing 9, and a hydraulic cylinder device 8A that controls the sliding movement of the hydraulic cylinder device 8A. It consists of a pair of left and right lift arms 10 etc. which are converted into vertical movement, and a hydraulic housing 9 covers the upper opening of the transmission case, and an arm support shaft 11 is installed on the housing 9.

The hydraulic cylinder device 8A is controlled by a hydraulic control valve 12 to neutralize, raise, and lower the hydraulic pressure from a pump (not shown). The position and draft are controlled by directional rotation operations.

Reference numeral 15 denotes a control link means, which is constructed of the following parts as shown in FIG. 2, and is built into the housing 9.

A position balancer 1 having a spool holding lever 16 pivotally supported at the upper part, one end slidingly engaged with the position cam 11A of the arm support shaft 11, and a middle part pivotally supported by a spring connector 17 and a cruciform cross.
8. One end is pivotally supported on the position control lever shaft,
Spring connector 17 and position balancer 1
8 and a horizontal draft pivoted to a vertical draft link 20 pivoted at one end to the draft control lever shaft and at the other end pivoted to the spring connector 17. It is composed of a link 21, a push metal fitting 22 that interlocks and connects the lower ends of the spool holding lever 16 and the spring connector 17, and a position feedback link (not shown) that interlocks and connects the upper part of the spool holding lever 16 and the position cam 11A. The draft cam 23, which is the target part of the present invention, is installed in the hydraulic housing 9 via a support device 24 according to the present invention shown in FIG.
The cam 23 actuates the vertical draft link 20 and the hydraulic control valve 1 via the control link means 15.
2 for draft control.

The draft cam 23 is one of the components that constantly controls the traction load of a working machine (not shown), such as a plow, which is attached to be towed via a three-point link 25, and the traction load applied from the lower link via the feedback link 26. The load F is sensed and the control valve 12 is actuated through the draft cam 23 to move the hydraulic system, specifically the lift arm 10, in the upward direction.

Therefore, the configuration will be described in detail while also referring to FIGS. 4 to 8.

The three-point link 25 consists of a top link 27 and a pair of left and right lower links 28.
Lift rod 29 from the middle of 8 and lift arm 10
It is linked and linked.

As shown in FIG. 1, the top link 27
Each lower link 28 is removably supported on both ends of a support 31 via a ball joint 28A, and the three-point link 25 is connected to a work machine. (plow, rotary) is installed.

As shown in FIG. 3, the support body 31 is inserted into the lower part of the vehicle body 1 across therethrough, and is inserted into both side walls 1A of the vehicle body 1.
It is installed in the horizontal direction via a ball joint type bearing body 32. Note that the bearing body 32 can be detachably fixed via bolts 33, and has a clearance 34 between the support body 31 and the vehicle body 1 or the bearing body 32. The lower link support body 31 essentially becomes a load spring member, and due to the traction load shown by arrow F in FIG. Arrow F in figure 4
1, it is made of a round material that bends and elastically deforms, and its traction load F1 acts as a bending deformation on the axial center of the support body 31 with the bearing body 32 as a support beam at both ends.

The feedback link device 26 is mainly composed of a first feedback link 35, a second feedback link 36, and a third feedback link 37.
5 has an engaging portion 38 with an open bottom at its upper portion, and a receiving cam 39 at its lower portion.

The receiving cam 39 has its screw rod 39 as shown in FIG.
A is provided by inserting the link stay 35A into the link stay 35A and screwing the nut 40, and the cam surface 39B is arc-shaped and faces and abuts the front of the circular support 31. A bullet 41 is provided that urges the support body 31 in the abutment direction.

Main body portion 35B of the first feedback link 35
As shown in FIG. 3, the receiving cam 39 is provided on the inner surface of the vehicle body side wall 1A along the height direction in order to avoid interference with the differential gear 4, and by providing the stay 35A on the main body portion 35B. The center portion between the bearing bodies 32 is opposed to the support body 31.

Furthermore, a mounting stay 3 is provided at the bottom of the main body portion 35B.
5C is fixed as shown in Figures 4 and 5,
A screw body 41 is inserted through a cylindrical boss 35D fixed to the stay 35C, thereby making the first feedback link 35 freely rotatable around a horizontal horizontal axis. The screw body 41 is screwed onto the side wall 1A of the vehicle body from outside the vehicle body as shown in FIG. 5, and ensures smooth rotation via the pusher 42.

The first feedback link 35 extends in the height direction from the pivot portion 43 such as the screw body 41 to avoid interference with the differential device 4, and its upper engaging portion 38 extends from the sixth
As shown in the figure, a window 1 is formed on the overhang 1B on the upper surface of the vehicle body.
The engaging portion 38 extends upwardly through C, has a tapered guide surface 38A as shown in the sixth figure, and is located substantially on the mating surface of the vehicle body 1 and the hydraulic housing 9.

As shown in FIGS. 6 and 7, the second feedback link 36 has a rotatable engaged portion 44 at its lower part.
and a third feedback link 37 at the top.
It has a pivot shaft 45 of. Further, the second feedback link 36 has a longitudinally intermediate portion that is rotatable about a horizontal axis via a pivot shaft 48 on a bracket 47 provided on the projecting portion of the hydraulic housing 9 with a fastener 46. The engaged portion 44 is fitted into and engaged with the engaging portion 38 in a depressed manner.

As shown in FIGS. 6 and 8, the third feedback link 37 has one end connected to the second feedback link 3.
It is pivotally attached to the pivot shaft 45 of No. 6, extends downward from the front, and is interlocked and connected to the draft cam support device 24.

That is, the draft cam support device 24 according to the present invention
As shown in FIG. 8, a threaded cylinder 50 is provided on the wall of the hydraulic housing 9 via a pusher 49 so as to be immovable in the cylinder length direction but rotatable around the axis, and a draft cam support shaft 51 is screwed into the threaded cylinder 50. Fittingly, the support shaft 5
The threaded portion 51A of No. 1 protrudes outside the housing 9 and screws into the nut 52, and has a tool engaging portion 5 at the end thereof.
It has 1B.

A draft cam 23 is fixed to the inner end of the support shaft 51, and a stay 50A is fixed to the threaded cylinder 50, and the front end of the third feedback link 37 is pivotally connected to the stay 50A by a pivot structure 53. are doing.

The assembly of the draft feedback link device 26 constructed as described above will be explained first, and the draft control operation will be explained next.

After installing the differential gear 4, the PTO transmission gear 5, and other driving systems and PTO transmission gears into the vehicle body 1,
A lower link support body 31 is installed in the rear lower part of the vehicle body 1 in the horizontal direction via a pair of bearing bodies 32.

The first feedback link 35, which has a receiving cam 39 at the bottom, is dropped into the upper opening of the vehicle body 1 so as not to interfere with the differential device 4, etc., and the receiving cam 3
The cam surface 39B of 9 is opposed to the center of the axial length of the support body 31, and the link 35 is screwed onto the screw body 41 from the outside on the vehicle body side wall 1A to support the cylinder boss 35D so as to be freely rotatable around the horizontal axis. Here, the first feedback link 35 is provided along the inside of the vehicle body and extends in the height direction via the pivot portion 43. At this time, bullet 4
1 shall be hung.

Next, the hydraulic system 8 is mounted on the upper surface of the vehicle body 1 in a closed manner, but the necessary parts are pre-assembled inside the hydraulic system 8, and the second feedback link 36 supported by the pivot shaft 48 The engaged portion 44 of the first feedback link 35 is brought into engagement with the engaging portion 38 of the first feedback link 35. This first feedback link 35 and the second
Since the engagement/separation portion with the feedback link 36 is located near the overlapping surface of the vehicle body 1 and the housing 9, assembly, disassembly, and adjustment are extremely advantageous.

It is desirable that the relative positional relationship between the draft cam 23 and the draft link 21 can be accurately and finely adjusted.This adjustment is performed by loosening the nut 52 and applying a tool to the engaging portion 51B, and then tightening the support shaft 51 into the threaded cylinder 50. It can be adjusted from the outside by rotating inside.

The disassembly process is performed in the reverse order as described above.

Therefore, if the work machine (plow) is towed and attached via the three-point link 25 and a load F greater than the set traction force is applied while the work continues, the support body 31, which also has a load spring, is pulled through the bearing body 32. bending deformation load F1
As a result, the position of the receiving cam 39 is changed around the pivot portion 43 as shown in FIG.

Since the receiving cam 39 has an arcuate cam surface 39B and is biased into engagement by the bullet 41, it can accurately bear the load F1.

When the load F1 is applied to the lower part, the upper part of the first feedback link 35 changes its position using the pivot 43 as a fulcrum as shown by the chain line in FIG. 6, but the amount of change is because the pivot 43 is closer to the bottom. The link 3 is connected to the link 3 through the engaged portion 44 of the second feedback link 36 which has an increased width and is rotatably fitted into the engaging portion 38.
6 undergoes a responsive angular displacement about the pivot shaft 48 as shown by the chain line in FIG. 15 etc., the control valve 12 is switched to the upward direction of the lift arm 10, and the working machine is lifted via the three-point link 25, thereby reducing the traction load.

In addition, when the working machine is a rotary, the load F acts in the opposite direction. 43 is placed below the cam 39, the second link 36 can be used as is. Also, when the work machine is rotary,
The cam 39 is opposed to the rear side of the support body 31, the pivot portion 43 is positioned above the cam 39, and the second link 36 and the third link 37 are reversely assembled so that the draft cam 23 rotates in the direction of the arrow. It becomes possible.

The present invention is a hydraulic system for a tractor with draft control in which a load spring 31 that is elastically deformed by a traction load F and a draft cam 23 are interlocked and connected by a feedback link 26, and a hydraulic control valve 12 is actuated via the draft cam 23. In 8, a threaded cylinder 50 having a female thread on the inner circumferential surface is provided in a hydraulic housing 9 containing a hydraulic cylinder device 8A so as to be immovable in the cylinder length direction but rotatable around an axis, and a threaded part 51A is provided at one end in the axial direction. The draft cam support shaft 51 having a threaded portion 51A is connected to the threaded cylinder 5.
0 female thread, and furthermore, the threaded portion 51A of the draft cam support shaft 51 or the threaded cylinder body 50
A nut 52 is fastened and loosely fitted into the threaded portion 51A of the hydraulic housing 9, and a draft cam 23 is fixed to the other end of the draft cam support shaft 51 in the axial direction. body 5
0 has a stay 50A in the hydraulic housing 9.
is fixed, a link 37 of the feedback link 26 is pivotally connected to the stay 50A, and a tool engaging portion 51B is provided at the outer end of the threaded portion 51A of the draft cam support shaft 51. Since the present invention relates to a draft cam support adjustment device for a tractor hydraulic system with draft control, it has the following advantages.

Since the draft cam support shaft 51 and the threaded cylinder body 50 have a double inner and outer structure, they can be made compact and can be easily assembled.

When adjusting by loosening the nut 52, the screw cylinder 5
0 is immovable in the cylinder length direction but rotatable around the axis, so the relative positional relationship (relative relationship around the axis) between the draft cam 23 and the feedback link stay 50A can be changed.

That is, the support shaft 51 of the draft cam 23 is connected to the threaded cylinder 50 rotatably provided in the hydraulic housing 9.
Since it has a lock nut 52 and an engaging part 51B at its outer end, external adjustment is possible by loosening the nut 52 and rotating it around the axis via the engaging part 51B. There is no need to disassemble the hydraulic system 8 or remove it from the vehicle body 1 every time.
Since the draft cam 23 rotates independently and its rotation is also based on a screw structure, fine adjustment is possible, and there is an advantage that the draft feedback link 26 is not misadjusted.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the rear part of the tractor, Fig. 2 is a side sectional view of the proposed device, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is a support body and the first feedback link. 5 is a sectional view taken along the line B-B in FIG. 4, FIG. 6 is a side view showing the detailed engagement relationship between the draft cam and each link, and FIG. 7 is a cross-sectional view taken along the line B-B in FIG. 6. 8 is a sectional view taken along the line D--D in FIG. 6. DESCRIPTION OF SYMBOLS 1... Vehicle body, 8... Hydraulic system, 9... Hydraulic housing, 12... Control valve, 23... Draft cam, 25... Three-point link, 26... Feedback link, 39... Reception cam , 50... Threaded cylinder body, 51... Support shaft, 52... Nut, 51B...
...Tool engagement part.

Claims (1)

[Claims for Utility Model Registration] A feedback link 26 connects a load spring 31 that is elastically deformed by a traction load F and a draft cam 23.
In the hydraulic system 8 for a tractor with draft control, which operates the hydraulic control valve 12 via the draft cam 23, a threaded cylinder 50 having a female thread on the inner peripheral surface has a hydraulic cylinder device 8A built therein. A draft cam support shaft 51 is provided in the housing 9 so as to be immovable in the cylinder length direction but rotatable around the axis, and has a threaded part 51A on one end in the axial direction.
0 female thread, and furthermore, the threaded portion 51A of the draft cam support shaft 51 or the threaded cylinder body 50
A nut 52 is fastened and loosely fitted into the threaded portion 51A of the hydraulic housing 9, and a draft cam 23 is fixed to the other end of the draft cam support shaft 51 in the axial direction. body 5
0 has a stay 50A in the hydraulic housing 9.
is fixed, a link 37 of the feedback link 26 is pivotally connected to the stay 50A, and a tool engaging portion 51B is provided at the outer end of the threaded portion 51A of the draft cam support shaft 51. Draft cam support adjustment device for tractor hydraulic system with draft control.