JP2008136409A - Yoke part support structure of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the yoke part support structure of a working vehicle, with which connection between the yoke part of the working vehicle and the input shaft of an implement is carried out smoothly. <P>SOLUTION: The yoke part support structure of a working vehicle is equipped with an autohitch 2 attached to the lifting and lowering links 18 and 19 of the working vehicle 1; a joint shaft 24 having a base end part connected freely swingingly to the PTO shaft 26 of the working vehicle 1; the yoke part 28 connected freely rotatably and swingingly connected to the tip part of the joint shaft 24; a yoke holder 29 that rotatably supports the yoke part 28 and is disposed at the autohitch 2 side; and a guide member for guiding the lifting and lowering of the yoke holder 29 and the guide member has a constitution, and is such that the lifting and lowering and the shake of the yoke holder 29 are guided, to arrange the input shaft 27 of the implement 3 and the yoke part 28 in a substantially straight line, at the connection operation of the implement 3 to the autohitch 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a yoke support structure for a work vehicle.

A guide member that guides the lifting and lowering of a yoke holder that rotatably supports the yoke portion in order to smoothly connect the input shaft of the working machine whose axial direction and height are not constant to the yoke portion to which the power of the work vehicle is transmitted. A yoke support structure for a work vehicle provided with a motor is known (Patent Document 1).
Japanese Patent Laid-Open No. 7-8014

  However, according to the yoke support structure of the work vehicle described in the above document, the vertical position of the yoke holder with respect to the auto hitch is guided by the guide member, but the swing of the yoke holder within the auto hitch is regulated within a certain range. The range is free. For this reason, when the yoke portion and the input shaft are connected, the axis of the yoke portion may be displaced from the axis of the input shaft due to the swinging of the yoke holder. In such a case, the connection between the yoke portion and the input shaft may occur. There was a problem that could not be performed smoothly.

  In order to solve the above-described problems, according to the yoke support structure of the present invention, first, the auto hitch 2 mounted on the lift links 18 and 19 of the work vehicle 1 and the base end portion on the PTO shaft 26 of the work vehicle 1. A joint shaft 24 connected, a yoke portion 28 rotatably connected to the tip of the joint shaft 24, a yoke holder 29 provided on the side of the auto hitch 2 that rotatably supports the yoke portion 28; A yoke portion support structure of a work vehicle configured by a guide member that guides the raising and lowering of the yoke holder 29, and the guide member is connected to the input shaft 27 of the work machine 3 during the connection operation to the auto hitch 2 of the work machine 3. A feature is that the yoke holder 29 is guided to move up and down and swing so that the yoke portion 28 is substantially in a straight line.

  Second, the guide member has a guide groove 33a having a mountain-shaped arc shape toward the work vehicle in a side view, and a guide that is accommodated in the guide groove 33a and slides the yoke portion 28 up and down along the guide groove 33a. It is characterized by comprising a protrusion 32.

  Third, the guide protrusion 32 is formed of an elastic body.

  According to the tractor yoke support structure of the present invention configured as described above, when the work implement is connected, the guide holder moves the yoke holder up and down and swings so that the input shaft of the work implement and the yoke are aligned. Therefore, there is an effect that the input shaft and the yoke portion can be smoothly connected.

  In addition, the guide member includes a guide groove having a mountain-shaped arc shape toward the tractor in a side view, and a guide protrusion that is accommodated in the guide groove and slides the yoke portion up and down along the guide groove. The yoke holder can be moved up and down and swinging reliably and smoothly.

  Furthermore, the guide protrusion accommodated in the guide groove is made of an elastic body, thereby preventing the yoke holder from vibrating.

  FIG. 1 is a side view of a tractor and work implement to which a yoke support structure for a work vehicle according to the present invention is applied. A work implement 3 as a rotary tiller is connected to a tractor 1 as a work vehicle via an auto hitch 2 so as to be movable up and down.

  The work machine 3 forms a frame portion by a gear case 4 (see FIG. 5) and a cylindrical portion 6 projecting from the left and right side surfaces of the gear case 4 in the left-right direction. A flange 7 is formed, and a top mast 8 projects upward from the upper surface of the gear case 4. A lower pin 9 is attached to the two flanges 7, and a top pin 11 is attached to the top mast 8. The work machine 3 is connected to the auto hitch 2 of the tractor 1 by the top pin 11 and a pair of left and right lower pins 9. Is done.

  2 and 3 are a perspective view and a rear view of the auto hitch. The auto hitch 2 includes a main frame 12 having an inverted U shape when viewed from the back, a top hook 13 fixed to the upper center of the main frame 12, and a lower plate 14 fixedly attached to the left and right lower portions of the main frame 12. The left and right lower plates 14, 14 connect the left and right lower frames 16 to form a frame portion.

  The top hook 13 is formed with an engagement groove 13 a that opens upward, and each lower plate 14 is formed with an engagement groove 14 a that opens rearward, and the work implement 3 is formed in the engagement groove 13 a of the top hook 13. The work implement 3 is connected to the auto hitch 2 by engaging the lower pins 9 of the work implement 3 corresponding to the top pins 11 and the locking grooves 14 a of the lower plate 14. The lower hooks 17 rotatably supported by the lower plates 14 release or lock the engagement between the lower plate 14 and the lower pins 9 to release or lock the connection of the work machine 3 to the auto hitch 2.

  The auto hitch 2 configured as described above is connected to the tractor 1 side by a top link 18 and a pair of left and right lower links 19 so as to be movable up and down. The top link 18 is supported by a top link support 21 fixed at the base end of the rear end of the tractor 1 so that the top link 18 can be turned up and down, and the tip side is turned up and down by a top hook 13 constituting the frame portion of the auto hitch 2. It is connected freely. On the other hand, each lower link 19 is supported at the base end on the lower portion of the rear end of the tractor 1 so as to be rotatable up and down, and at the distal end is connected to the corresponding lower plate 14 of the auto hitch 2 so as to be rotatable up and down.

  A pair of left and right lift arms 22 is pivotally supported at the rear end of the tractor 1 so as to be swingable up and down, and a middle portion of the corresponding lower link 19 is connected to the tip of each lift arm 22 via a lift rod 23. The automatic hitch 2 and the work implement 3 are driven up and down by the hydraulic operation of the lift arm 22.

  Between the tractor 1 and the auto hitch 2, together with the top link 19 and the lower link 21, a joint shaft 24 in the front-rear direction for transmitting power from the tractor 1 side to the work implement 3 as shown in FIG. The front end of the joint shaft 24 is connected to a PTO shaft 26 protruding rearward from the lower portion of the rear end of the tractor 1, and the rear end is connected to a yoke portion 28 connected to the input shaft 27 (see FIG. 5) of the work machine 3. Yes.

  A connecting portion between the PTO shaft 26 and the joint shaft 24 and between the joint shaft 24 and the yoke portion 28 forms a universal joint, and the power of the PTO shaft 26 is transmitted to the yoke portion 28. An insertion hole 28a into which the input shaft 27, which is a spline shaft, is inserted is formed at the rear end of the yoke portion 28. By the above mechanism, the power of the yoke portion 28 is transmitted to the input shaft 27 of the work machine 3.

  The yoke portion 28 is rotatably supported by a yoke holder 29 which is a unitized bearing portion. As shown in FIGS. 2 and 3, the yoke holder 29 is configured by a cylindrical bearing 31 having a substantially circular shape when viewed from the back, and guide protrusions 32 protruding in the left-right direction from the left and right sides of the bearing 31. Yes. The guide protrusion 32 is made of an elastic member such as rubber.

  On the other hand, a pair of left and right supports 33 project upward from the center of the lower frame 16. The left and right supports 33, 33 extending in the vertical direction are formed in a substantially U-shape (or inverted U-shape) in plan view opposed to each other. A guide groove 33a having an opening on the upper side and the inner side in the left-right direction is formed.

  The guide protrusions 32 of the yoke holder 29 are inserted from the upper openings of the guide grooves 33a of the left and right supports 33, and the guide grooves 33a (or the guide members 33) and the guide protrusions 32 are engaged with each other, so that the yoke holder 29 is automatically hitched. Support to the side.

  FIG. 4A is a perspective view of the joint shaft, the yoke portion, and the yoke holder, and FIG. 4B is a side sectional view showing an engagement state between the guide protrusion and the guide groove. The guide groove 33a is formed in a side-view circular arc shape that is curved in a mountain shape toward the work vehicle side, and the front and rear surfaces of the guide projection 32 are also circular in side view corresponding to the shape and front-and-rear width of the guide groove 33a. It is molded into an arc shape.

  According to the support structure of the yoke portion configured as described above, since the guide protrusion 32 corresponding to the shape of the guide groove 33a is engaged with the guide groove 33a, the yoke portion 28 supported by the yoke holder 29 has the guide groove 33a. And the swing angle of the yoke portion 28 (yoke holder 29) in the auto hitch 2 is determined corresponding to each lift position. That is, ascending / descending and swinging of the yoke portion 28 is guided by the engagement between the guide protrusion 32 and the guide groove 33a.

  FIGS. 5A to 5D are side views showing a connecting process between the yoke portion and the input shaft when the work implement is connected to the auto hitch. When the work implement 3 is connected to the auto hitch 2, when the top pin 11 is engaged with the top hook 13, the work implement 3 as a whole pivots around the top pin 11 as a pivot, and the input shaft 27 of the work implement 3 is connected to the yoke. The part 28 is approached (see FIG. 9A).

  Next, when the tip of the input shaft 27 is inserted into the insertion hole 28a by being guided by the tapered surface formed in the insertion hole 28a of the yoke part 28, the yoke part 28 is guided up and down along the guide groove 33a. With the guidance, the swing angle of the yoke portion 28 is guided so that the joint shaft 24, the yoke portion 28, and the input shaft 27 are substantially in a straight line (see FIG. 5B).

  Then, from the start of the connecting operation of the input shaft 27 to the yoke portion 28, the entire input shaft 27 is completely inserted into the insertion hole 28 a of the yoke portion 28, and the lower pin 9 of the work implement 3 is engaged with the lower plate 14 of the auto hitch 2. By the guide member composed of the guide protrusion 32 and the guide groove 33a so that the joint shaft 24, the yoke portion 28 and the input shaft 27 are in a substantially straight line until the end of the coupling operation engaged with the joint groove 14a. The raising and lowering and swinging of the yoke portion 28 is guided (see (C) to (D) in the figure).

  According to the yoke support structure in the work vehicle configured as described above, since the yoke and the input shaft are in a straight line during the connecting operation to the input shaft 27 to the yoke 28, the power shaft is connected. Performed smoothly. Further, since the guide protrusion 32 is made of an elastic member, troubles such as vibration of the yoke portion due to the rotational reaction force during power transmission can be prevented. Furthermore, since the unintended behavior of the yoke holder is suppressed by the engagement between the guide protrusion 32 and the guide groove 33a, troubles associated therewith are also prevented.

It is a side view of a tractor and a working machine. It is a perspective view of an auto hitch. It is a rear view of an auto hitch. (A) is a perspective view of a joint shaft, a yoke portion, and a yoke holder, and (B) is a side sectional view showing an engagement state between a guide protrusion and a guide groove. (A)-(D) are side views which show the connection process of the yoke part and input shaft at the time of connecting a working machine with an auto hitch.

Explanation of symbols

1 Tractor (work vehicle)
2 Auto hitch 3 Work implement 18 Top link (elevating link)
19 Lower link (elevating link)
24 Joint shaft 27 Input shaft 28 Yoke part 29 Yoke holder 32 Guide protrusion (guide member)
33a Guide groove (guide member)

Claims (3)

  An auto hitch (2) mounted on the lift links (18), (19) of the work vehicle (1), and a joint shaft (24) having a base end connected to the PTO shaft (26) of the work vehicle (1). A yoke part (28) rotatably and swingably connected to the tip of the joint shaft (24), and a yoke holder (on the auto hitch (2) side) that rotatably supports the yoke part (28). 29) and a yoke support structure for a work vehicle configured by a guide member that guides the raising and lowering of the yoke holder (29), and the guide member is connected to the auto hitch (2) of the work machine (3). At this time, the yoke of the working vehicle is configured to guide the raising and lowering and swinging of the yoke holder (29) so that the input shaft (27) and the yoke portion (28) of the working machine (3) are substantially in a straight line. Part support structure.   A guide member (33a) having a mountain-shaped arc shape toward the work vehicle in a side view, and a yoke portion (28) accommodated in the guide groove (33a) along the guide groove (33a) The yoke support structure for a work vehicle according to claim 1, further comprising a guide protrusion (32) for sliding up and down.   The yoke support structure for a work vehicle according to claim 2, wherein the guide protrusion (32) is made of an elastic body.

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