JP2007270975A - Pto clutch operation structure for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and inexpensive PTO clutch operation structure for a working machine, wherein a PTO brake mounted on the transmission downstream side of a PTO clutch can be brake-operated in linkage with the clutch off-operation of a clutch member of the PTO clutch for cutting the PTO clutch off to apply braking to a driven side. <P>SOLUTION: The clutch member 34 and a clutch operation tool 48 are mechanically linked with each other so that the displacement of the clutch member 34 can be operated by the clutch operation tool 48 to be manually operated. An operation tool holding means fixes and holds the clutch operation tool 48 onto a clutch off-operation position OFF. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an operation structure of a PTO clutch provided in a work machine such as an agricultural tractor.

As a PTO clutch operation structure of an agricultural tractor, for example, as disclosed in Patent Document 1, a PTO brake is provided on the lower transmission side of a hydraulically operated multi-plate PTO clutch, and the clutch is operated in the PTO clutch. A structure in which the PTO brake is braked in conjunction with the movement of the piston member in the clutch disengagement direction, so that the work device in which the transmission of the PTO power is interrupted can be prevented from continuing to rotate due to inertia. Are known.
JP 2005-83488 A

  The above PTO clutch operation structure can perform powerful clutch operation and braking operation by hydraulic pressure, but requires a hydraulic device such as a switching valve for clutch operation, hydraulic piping, etc., and the structure is complicated and expensive. It was.

  The present invention has been made paying attention to such a point, and it is an object of the present invention to simplify the structure and reduce the cost of applying the braking to the driven side by disengaging the PTO clutch.

In a first aspect of the present invention, there is provided a PTO clutch operation structure for a work machine in which a PTO brake is provided on a lower transmission side of a PTO clutch, and the PTO brake is braked in conjunction with a clutch disengagement operation of a clutch member in the PTO clutch. ,
The clutch member and the clutch operating tool are mechanically interlocked so that the clutch member can be displaced by a manually operated clutch operating tool, and an operating tool holding means for fixing and holding the clutch operating tool at the clutch disengagement operation position is provided. It is characterized by that.

  According to the above configuration, the clutch operating tool that is mechanically linked to the clutch member is operated to disengage the clutch and is held in that position, so that braking is continued to be applied to the lower transmission side from the PTO clutch in the PTO transmission system in which transmission is interrupted. It is possible to reliably prevent the working device driven by the PTO power from continuing to rotate due to inertia after the PTO clutch is disengaged.

According to a second invention, in the first invention,
The clutch member and the clutch operating tool are interlocked and connected via a link mechanism, and an operating tool holding means is provided that allows the clutch operating tool to be switched over between the clutch operating position and the clutch disengaging operating position beyond the dead point. It is what is.

  According to the above configuration, when the clutch operating tool is operated to the clutch disengagement operation position, a return biasing force in the clutch engagement direction due to the reaction force of the brake operation is generated, but when the clutch operation tool exceeds the dead point in the clutch disengagement direction, The return biasing force in the clutch engaging direction becomes a force for operating the clutch operating tool in the clutch disengaging direction, and the clutch operating tool can be reliably held at the clutch disengaging operation position.

According to a third invention, in the second invention,
The operation tool holding means is incorporated in the link mechanism.

  According to the above configuration, a part of the link mechanism can be used as a component member of the operating tool holding means that exceeds the dead point, which is more effective in simplifying the structure of the operating tool holding means.

A fourth invention is the invention according to any one of the first to third inventions,
A rear PTO shaft projecting from the rear of the fuselage and a mid PTO shaft projecting from the lower part of the fuselage are arranged on the lower transmission of the PTO brake.

  According to the above configuration, the PTO brake can be applied to both the rear PTO shaft and the mid PTO shaft, and is connected when using either the rear PTO shaft or the mid PTO shaft and when using both at the same time. The inertial rotation of the working device can be appropriately suppressed.

A fifth invention is the fourth invention, wherein:
Under the transmission of the PTO brake, a transmission mode for transmitting PTO power only to the rear PTO shaft, a transmission mode for transmitting PTO power only to the mid PTO shaft, and a transmission for transmitting PTO power to the rear PTO shaft and the mid PTO shaft. A PTO mode selection mechanism capable of selecting one of the modes is provided.

  According to the above configuration, the driving mode of the work device driven by the PTO power can be selected in three ways, and the rear PTO shaft and the mid PTO shaft can be accurately braked in each mode, and the versatility of the work can be improved.

A sixth invention is the invention according to any one of the first to fifth inventions,
A one-way clutch that allows a preceding rotation on the driven side is provided at a position where the PTO clutch is transmitted well.

  According to the said structure, it can avoid that a driving | running | working transmission system is driven by the reverse drive by the inertia of the PTO transmission system at the time of releasing a main clutch, and a body moves.

  FIG. 1 shows an entire side surface of a four-wheel drive agricultural tractor as an example of a work machine. This agricultural tractor has a structure in which a body body is configured by connecting a clutch housing 2 connected to a rear portion of an engine 1 and a transmission case 3 via a housing frame 4 made of sheet metal. A front axle case 7 having a steering front wheel 6 is supported in a freely rolling manner on a front frame 5 extending forward from the lower part of the engine 1, and a rear wheel 8 is mounted on the rear part of the transmission case 3. Yes.

  The transmission case 3 is configured by connecting a front case 3f, a mid case 3m, and a differential case 3d. A rear wheel 8 is pivotally supported on the left and right of the differential case 3d, and a lift arm 9 is provided above the differential case 3d. The three-point link mechanism 11 for connecting the work device is lifted and lowered by a lift arm 9 that is hydraulically driven. A rear PTO shaft 12 is provided to project rearward from the rear surface of the differential case 3d, and a mid PTO shaft 13 is provided to project forward from the lower portion of the midcase 3m.

As shown in FIG. 2, a main gear transmission unit 15 and a forward / reverse switching unit 16 are incorporated in the front case 3f, and a sub gear transmission unit 17 is incorporated in the mid case 3m.
The main gear transmission unit 15 is configured to shift the engine power input to the input shaft 18 in three stages and transmit it to the intermediate shaft 19, and the forward / reverse switching unit 16 corrects the transmission power of the intermediate shaft 19. It is configured to rotate or reversely transmit to the output shaft 20, so that a main shift of three forward speeds and three reverse speeds can be performed inside the front case 3f.

  More specifically, a small-diameter idle gear G1 and a large-diameter idle gear G2 are mounted on the input shaft 18 of the main gear transmission unit 15, and a medium-diameter shift gear G3 is interposed between the small-diameter and large-diameter idle gears G1, G2. Are attached to the intermediate shaft 19 with a large-diameter gear G4 and a small-diameter gear G5 that are always meshed with the small-diameter idle gear G1 and the large-diameter idle gear G2, respectively, and a medium-diameter gear that can be meshed with the shift gear G3. G6 is fixed. By shifting the shift gear G3 to the front position and engaging the boss of the small-diameter free gear G1 with a spline, the intermediate shaft 19 is driven at low speed (first speed) via the small-diameter free gear G1 and the large-diameter gear G4. Transmission is performed, and the shift gear G3 is shifted to the intermediate position of the front and rear and directly engaged with the intermediate gear G6, so that the intermediate shaft 19 is transmitted with medium speed (second speed), and the shift gear 3 is shifted to the rear position. By spline engagement with the boss portion of the large-diameter idle gear G2, high-speed (third speed) power transmission is made to the intermediate shaft 19 via the large-diameter idle gear G2 and the small-diameter gear G5.

  The output shaft 20 includes a forward transmission idle gear G8 that is always engaged with the gear G7 of the intermediate shaft 19, and a reverse transmission idle gear that is always engaged with the gear G9 of the intermediate shaft 19 via the reverse gear G10. G11 is provided, and the shift sleeve S, which is spline-fitted to the output shaft 20, is shifted and selectively engaged with the boss portion of the normal rotation transmission idle gear G8 or the reverse rotation transmission idle gear G11. Thus, the transmission power of the intermediate shaft 19 is forwardly or reversely transmitted to the output shaft 20.

  The sub-gear transmission 17 performs a three-stage shift between the transmission shaft 21 and the output shaft 22 that are butt-coupled to the output shaft 20, and the differential gear transmission 17 is connected to the differential gear via a bevel pinion gear Gp provided at the rear end of the output shaft 22. The mechanism D is driven and the left and right rear wheels 8 are differentially driven.

  More specifically, a large-diameter loosely fitted gear G12 and a small-diameter loosely fitted gear G13 are mounted before and after the transmission shaft 21, and a shift gear G14 that is shifted between the large-diameter and small-diameter loosely fitted gears G12 and G13 is provided. A spline is attached. The bevel pinion shaft 22 is fixed with a small-diameter gear G15 that always meshes with the large-diameter loose-fit gear 12, a large-diameter gear G16 that always meshes with the small-diameter loose-fit gear G13, and a medium-diameter gear G17 that can mesh directly with the shift gear G14. ing. By shifting the shift gear G14 rearward and engaging the boss portion with the boss portion of the small-diameter free-fit gear G13, transmission at the gear ratio of the small-diameter free-fit gear G13 and the large-diameter gear G16 results in "low speed". Then, by shifting the shift gear G14 to the intermediate position of the front and rear and directly meshing with the intermediate gear G17, "medium speed" is brought about by transmission in the gear ratio between the shift gear G14 and the intermediate gear G17, and the shift gear G14 Is shifted forward and the boss portion is engaged with the boss portion of the large-diameter loosely fitted gear G12, so that transmission at a gear ratio between the large-diameter loosely fitted gear 12 and the small-diameter gear G15 provides "high speed". It is.

  An output gear G18 for power transmission to the front wheels 6 is fixed to the front end portion of the bevel pinion shaft 22 that is shifted as described above, and the front wheel drive transmission is extended over the front case 3f and the mid case 3m. A shaft 23 is penetratingly supported, and the power extracted from the front wheel drive transmission shaft 23 is transmitted to the front axle case 7 through a front wheel transmission structure (not shown). A shift gear G19 is spline-fitted to the rear end of the front wheel drive transmission shaft 23, and the shift gear G19 is shifted forward and meshed with the output gear G18 of the bevel pinion shaft 22, thereby driving the rear wheel drive speed. A four-wheel drive state in which front-wheel drive power at a speed synchronized with the front-wheel drive is taken out from the front-wheel drive transmission shaft 23, and the shift gear G19 is shifted rearward to release the engagement with the output gear G18. 6 is turned off, and a rear two-wheel drive state by only the rear wheel 8 is brought about.

Next, the PTO transmission system will be described.
The rear end of the input shaft 18 penetratingly supported at the upper part of the front case 3f and the PTO transmission shaft 25 supported across the front case 3f and the midcase 3m are concentrically arranged and arranged. The input shaft 18 and the PTO transmission shaft 25 are interlocked and connected via a one-way clutch 26 and a PTO clutch 27 provided at the site. A relay transmission shaft 28 is concentrically connected to the rear end of the PTO transmission shaft 25, and a small-diameter gear G20 provided at the rear end portion of the relay transmission shaft 28 and a large-diameter gear G21 provided on the rear PTO shaft 12. The rear PTO shaft 12 is engaged at a constant speed independently of the traveling system.

  As shown in FIG. 4, the one-way clutch 26 is spline-mounted on the rear end portion of the input shaft 18 so as to be slidable back and forth, and is slidably biased rearward by a spring 29, and a PTO system. The transmission shaft 25 includes a driven transmission member 31 that is loosely fitted to the front end of the transmission shaft 25 so as not to be displaced in the axial direction. The clutch member 30 and the transmission member 31 are opposed to each other at the opposed ends. Occlusion is interlocked via the part 32. The inclined claw engaging portion 32 is inclined so that the driven-side transmission member 31 can be rotated in advance in the input shaft rotation direction with respect to the clutch member 30 while the clutch member 30 is pushed and displaced forward against the spring 29. The direction is set, and the input shaft 18 is prevented from being rotated by the reverse drive from the PTO transmission system. In other words, when a working device having a large rotational inertia is driven to rotate by PTO power, the input shaft 18 is moved by the rotational inertia of the working device even if the main clutch is disengaged and the traveling is stopped and the transmission to the PTO transmission system is stopped. It is avoided in advance that the vehicle is driven to continue running.

  As shown in FIG. 4, the PTO clutch 27 includes the transmission member 31 disposed on the driven side of the one-way clutch 26, a transmission collar 33 loosely supported by the PTO transmission shaft 25, and the transmission collar 33. This is a meshing clutch comprising a clutch member 34 fitted on a spline so as to be slidable back and forth. By causing the clutch member 34 to slide forward and engage across the transmission member 31 and the transmission collar 33, a “clutch-on” state in which power is transmitted from the transmission member 31 to the transmission collar 33 is brought about. Then, the clutch member 34 is slid rearward to release the engagement with the transmission member 31, thereby bringing about a “clutch disengagement” state in which power transmission from the transmission member 31 to the transmission collar 33 is interrupted.

  A PTO brake 35 that prevents inertial rotation on the lower side of the transmission in conjunction with the “clutch disengagement” operation is disposed at a location behind the PTO clutch 27. The PTO brake 35 is configured as a multi-plate friction brake in which a friction plate 36 that is splined to the transmission collar 33 and a brake plate 37 that is non-rotatably engaged with the peripheral wall of the midcase 3m are alternately superposed. Yes. A coil spring 38 is interposed between the clutch member 34 and the PTO brake 35 in the PTO clutch 27. The coil spring 38 has a free length that is not compressed and deformed in the “clutch engaged” state in which the clutch member 34 is slid forward. At this time, the PTO brake 35 is not braked. In the “clutch disengagement” state in which the clutch member 34 is slid rearward, the displacement of the clutch member 34 is transmitted to the PTO brake 35 via the coil spring 38, and the friction plate 36 and the brake plate 37 are superposed and pressure-contacted. 33 is rotationally braked.

  Behind the PTO brake 35 is a transmission mode in which the PTO power transmitted to the transmission collar 33 is transmitted only to the rear PTO shaft 12, a transmission mode in which the PTO power is transmitted only to the mid PTO shaft 13, and the PTO power to the rear PTO. A PTO mode selection mechanism 40 is provided that can select either the transmission mode transmitted to the shaft 12 or the mid PTO shaft 13.

  The mid PTO shaft 13 is supported by a power take-out case 3c connected to the lower surface of the mid case 3m, and the PTO power taken out from the output gear G22 loosely fitted to the rear portion of the PTO transmission shaft 25 is transferred to the mid PTO shaft 13. Gears are transmitted. In other words, the output gear G22 is interlocked with the gear G24 loosely fitted to the transmission shaft 21 of the traveling system via the gear G23 loosely fitted to the front wheel drive transmission shaft 23, and the gear G25 integrated with the gear G24 is integrated. The gear G26 integrally formed with the mid PTO shaft 13 is engaged with and engaged with a gear G26 loosely fitted to the intermediate support shaft 39.

  The PTO mode selection mechanism 40 is configured to select the PTO power take-out mode as described above by shifting the shift member 41 spline-fitted to the inner periphery of the transmission collar 33 back and forth. When the member 41 is shifted to the foremost position, the shift member 41 is engaged with only the spline portion 25a of the PTO transmission shaft 25 on its inner periphery, and relayed to the transmission collar 33 via the PTO clutch 27. It is transmitted only to the rear PTO shaft 12 via the transmission shaft 28.

  As shown in FIG. 4, when the shift member 41 is shifted to the front / rear intermediate position, the shift member 41 is splined over the spline portion 25a of the PTO transmission shaft 25 and the boss portion of the output gear G22. The power transmitted to the transmission collar 33 via the clutch 27 is transmitted to the rear PTO shaft 12 and also to the mid PTO shaft 13.

  When the shift member 41 is shifted to the rearmost position, the shift member 41 is splined only to the boss portion of the output gear 22, and the power transmitted to the transmission collar 33 via the PTO clutch 27 is the mid PTO shaft 13. Only transmitted to.

  The operation structure of the PTO clutch 27 is shown in FIGS.

  The clutch member 34 of the PTO clutch 27 is engaged with a shift fork 46 that is swingably mounted on a side wall of the mid case 3m via a fork support shaft 45, and a support bracket 47 is provided on the side of the driving unit. A clutch lever (clutch operating tool) 48 erected and arranged so as to be able to swing back and forth and the outer end portion of the fork support shaft 45 are interlocked and connected via a link mechanism 50.

  The link mechanism 50 includes an operation arm 51 pivotally connected to the support bracket 47, a clutch arm 52 connected and fixed to an outer end of the fork support shaft 45, a free end of the operation arm 51, and a free play of the clutch arm 52. It is composed of a link rod 53 for connecting the end and a toggle link 54 for interlockingly connecting the clutch lever 48 and the operation arm 51, and the clutch lever is operated to the front clutch engagement operation position (ON). Thus, the clutch member 34 is shifted forward to bring about a “clutch engaged” state, and the clutch lever 48 is operated to the rear clutch disengagement operation position (0FF), whereby the clutch member 34 is shifted rearward. A state in which the clutch is disengaged and the PTO brake 35 is braked is brought about.

  The toggle link 54 has a function as an operation tool holding means for switching the clutch lever 48 over the dead point between the clutch engagement operation position (ON) and the clutch disengagement operation position (0FF). That is, when the clutch lever 48 is operated rearward from the clutch engagement operation position (ON), the upper fulcrum p of the toggle link 54 moves rearward along an arc locus centered on the fulcrum q of the clutch lever 48. Thus, the lower fulcrum r of the toggle link 54 is displaced downward along an arc locus centered on the fulcrum s of the operation arm 51, whereby the operation arm 51 is swung downward and the clutch member 34 moves rearward (clutch disengagement direction). I will do it.

  When the lower fulcrum r of the toggle link 54 reaches an imaginary line (dead point) L connecting the upper fulcrum p of the toggle link 54 and the fulcrum q of the clutch lever 48, the operation arm 51 is swung downward most. At this time, the PTO clutch 27 is completely disconnected and is in a braking state in which the PTO brake 35 is pressed via the compression-deformed coil spring 38. When the clutch lever 48 is further swung back and moved to the operation limit position where it contacts the proximal end boss 51 a of the operation arm 51, the lower fulcrum r of the toggle link 54 is moved to the toggle link 54 as shown in FIG. 7. The imaginary line L connecting the upper fulcrum p and the fulcrum q of the clutch lever 48 is slightly over the front. In this state, the clutch member 34 is slid forward by the elastic restoring force of the coil spring 38 in the compression deformed state. The clutch arm 52 is urged to swing upward by the forward urging force acting on the clutch member 34, and the operation arm 51 linked to the clutch arm 52 is also urged to swing upward. As a result, the lower fulcrum r of the toggle link 54 is pushed upward and forward from the dead point L, and the clutch lever 48 is urged to swing backward, so that the clutch lever 48 is held at the clutch release operation position (0FF). It is done.

  The support bracket 47 is provided with a limit switch 56 that detects that the operating arm 51 is operated downward and is in the clutch disengagement position. The limit switch 56 detects that the PTO clutch 27 is disengaged. The limit switch 56 is connected to the engine start circuit so that the engine 1 can be started only in the state where the engine is in the open state.

  A disc 57 is fixed to the outward projecting portion of the fork shaft 45, and a detent mechanism 60 for engaging a spring-detented detent ball 59 with a notch 58 formed on the outer periphery of the disc 57 is provided. . The detent mechanism 60 is engaged when the clutch member 34 is in the clutch engagement position, so that the clutch engagement state is stably maintained. The substrate 61 a of the holder 61 that supports the detent ball 59 is engaged with the outer peripheral groove 62 of the fork shaft 45 and used as a retaining member for the fork shaft 45.

[Other Examples]
(1) In the above-described embodiment, the clutch lever 48 is moved past the dead point L and the clutch engagement operation position (ON) and the clutch disengagement operation are connected to the link mechanism that interlocks and connects the clutch lever (clutch operating tool) 48 and the fork shaft 45. Although the operation tool holding means for switching and moving the position (OFF) is incorporated, the clutch lever 48 and the fork shaft 45 are interlocked and connected by a simple link mechanism, and the clutch lever 48 is used by a dedicated operation tool holding means. A structure that holds the position may be used.

  (2) As shown in FIG. 9, as a simple operation tool holding means, a clutch lever (clutch operation tool) 48 is configured to be operable or deformable in a lateral direction perpendicular to the swing operation direction. The clutch lever 48 can be locked to the provided recess 66 and can be locked and held at the clutch disengagement operation position (OFF).

  (3) The operation tool holding means may be configured by using a curved toggle link 53 for passing the dead point.

  (4) As a PTO operating tool for operating the PTO clutch 27 and the PTO brake 35, a PTO pedal that can be stepped forward and backward can be used.

Overall side view of tractor Longitudinal side view of transmission structure Side view of gear train with transmission structure Longitudinal side view showing the PTO clutch with the clutch engaged Longitudinal side view showing the PTO clutch in the clutch disengaged state Side view showing PTO clutch operation structure with clutch engaged Side view showing the PTO clutch operation structure in the clutch disengaged state Longitudinal front view of PTO clutch operating structure The top view which shows another Example of the operation tool holding means in a PTO clutch operation structure

Explanation of symbols

26 One-way clutch 27 PTO clutch 35 PTO brake 34 Clutch member 40 PTO mode selection mechanism 48 Clutch operating tool (clutch lever)
50 Link mechanism L Dead center

Claims (6)

In the PTO clutch operation structure of the working machine, which is equipped with a PTO brake on the lower transmission side of the PTO clutch and configured to brake the PTO brake in conjunction with the clutch disengagement operation of the clutch member in the PTO clutch,
The clutch member and the clutch operating tool are mechanically interlocked so that the clutch member can be displaced by a manually operated clutch operating tool, and an operating tool holding means for fixing and holding the clutch operating tool at the clutch disengagement operation position is provided. A structure for operating a PTO clutch of a working machine.   The operation member holding means for interlockingly connecting the clutch member and the clutch operation tool through a link mechanism, and for switching the clutch operation tool between a clutch engagement operation position and a clutch disengagement operation position beyond a dead point. The PTO clutch operating structure for a working machine according to claim 1, which is equipped.   The PTO clutch operation structure for a work machine according to claim 2, wherein the operation tool holding means is incorporated in the link mechanism.   The work according to any one of claims 1 to 3, wherein a rear PTO shaft projecting from a rear part of the fuselage and a mid PTO shaft projecting from a lower part of the fuselage are arranged on the lower transmission of the PTO brake. PTO clutch operation structure of the machine.   Under the transmission of the PTO brake, a transmission mode for transmitting PTO power only to the rear PTO shaft, a transmission mode for transmitting PTO power only to the mid PTO shaft, and a transmission for transmitting PTO power to the rear PTO shaft and the mid PTO shaft. 5. The PTO clutch operating structure for a working machine according to claim 4, wherein a PTO mode selecting mechanism that can select either mode is provided.   The PTO clutch operation structure for a working machine according to any one of claims 1 to 5, wherein a one-way clutch that allows a preceding rotation on the driven side is provided at a location where the PTO clutch is transmitted well.

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