JP2005263117A - Power take-off device for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PTO rear cover enabling switching from a mechanical PTO clutch mechanism to a hydraulic PTO clutch mechanism while modularizing a PTO valve. <P>SOLUTION: The PTO rear cover 3c is mounted to the rear end part of the rear housing 3 of the machine body in a power take-off device for a working vehicle. The PTO valve is integrally provided on the PTO rear cover 3c, and an oil passage and a port communicating the PTO valve 72 with the PTO clutch 28 are formed in the PTO rear cover 3c. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power take-out device for a work vehicle, and more particularly, to a structure of a PTO rear cover attached to a rear housing rear end of the power take-out device.

Conventionally, a power take-out device for a work vehicle is known as described in, for example, Patent Document 1.
In the power take-off device described in Patent Document 1, the rear end portion of the rear housing of the fuselage is covered with the PTO rear cover, and the brake support shaft of the brake that brakes the clutch housing of the PTO clutch with the PTO rear cover, the clutch shaft, In addition, the sub-assembly is configured by supporting the end of the PTO shaft, and the sub-assembly can be incorporated into the airframe at the same time that the PTO rear cover is mounted on the rear end of the rear housing.

JP 2003-94970 A

However, the conventional PTO rear cover mounted on the power take-off device of a work vehicle does not consider the modularization of the PTO valve, and the switching from the mechanical PTO clutch mechanism to the hydraulic PTO clutch mechanism is not possible. It was not a consideration.
Further, in the power take-off device of the conventional configuration, since the position of the PTO valve is away from the PTO clutch mechanism, a loss occurs when the pressure oil passes through the piping disposed between the PTO valve mechanism and the hydraulic pressure control. The pressure changed and the control was unstable.

In view of such problems, the present invention provides a PTO rear cover that enables modularization of a PTO valve and enables switching from a mechanical PTO clutch mechanism to a hydraulic PTO clutch mechanism. .
Moreover, the hydraulic loss is reduced, stable hydraulic control is realized, and maintenance of the PTO valve and the hydraulic port is improved.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, according to the first aspect of the present invention, there is provided a power take-off device for a work vehicle in which a PTO rear cover is attached to the rear end of the rear housing of the fuselage. Are formed in the PTO rear cover.

  According to a second aspect of the present invention, a hydraulic pressure setting valve is arranged on the airframe body side, pressure oil supplied from the valve is supplied to the PTO valve, and pressure oil is supplied to the PTO clutch and the PTO brake by the PTO valve. It is a thing.

  According to a third aspect of the present invention, the PTO valve is arranged on the upper part of the PTO rear cover.

  According to a fourth aspect of the present invention, an oil inspection window is provided on the PTO rear cover.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, the modularization of the hydraulic PTO clutch can be realized. Then, by mounting / removing the PTO rear cover, it is possible to easily switch to the specification with or without the hydraulic clutch. In addition, since the oil passage connected to the PTO valve is disposed in the PTO rear cover, hydraulic pressure management and hydraulic pressure control are facilitated. In addition, the PTO clutch and the PTO valve can be arranged close to each other, the hydraulic loss is reduced, the responsiveness is improved, and the reliability can be improved.

  In claim 2, since the PTO rear cover is formed so as to cover the rear housing, and the all hydraulic clutch control valve connected to the PTO clutch and the PTO brake mechanism is mounted on the cover, the work can be performed from the rear and the control is performed. Since the valves are concentrated, maintainability can be improved.

  In claim 3, a necessary space around the PTO shaft can be secured. Further, the PTO valve is a modulation mechanism and is close to the PTO clutch, so that stable hydraulic control can be realized without any hydraulic loss. Further, maintenance work and the like can be easily performed from the upper rear side.

  According to the fourth aspect of the present invention, the amount of hydraulic oil can be easily recognized from the rear without using an oil inspection rod or the like. Also, the number of parts can be reduced.

Next, the best mode for carrying out the invention will be described.
FIG. 1 is a schematic partially developed longitudinal sectional view showing the overall configuration of a transmission mechanism of a tractor according to an embodiment of the present invention, FIG. 2 is a longitudinal side view of the rear part of the tractor body, and FIG. 4 is a plan view, FIG. 5 is a front view, FIG. 6 is a cross-sectional view taken along the line AA in FIG. 5, FIG. 7 is a cross-sectional view taken along the line BB in FIG. FIG. 9 is a cross-sectional view taken along the line CC in FIG. 6, FIG. 10 is a cross-sectional view taken along the line DD in FIG. 6, and FIG. 11 is a hydraulic circuit diagram of the tractor.

First, the whole structure of the tractor provided with the PTO rear cover according to the present invention will be described.
As shown in FIG. 1, the tractor body housing includes a front housing 1, an intermediate housing 2, and a rear housing 3 that are connected in the front-rear direction. The front housing 1 has a support wall portion 1a that is integral with the middle portion, and is attached to and supported by the front housing 1 at a position that substantially bisects the front housing 1 on the rear side of the support wall portion 1a. And a second bearing frame 5 attached to and supported by the rear end of the front housing 1. The second bearing frame 5 may be attached to and supported by the front end of the intermediate housing 2.

  The intermediate housing 2 has a supporting wall portion 2a integral with the intermediate portion, and the rear housing 3 has a front wall 3a, a support wall 32 at the intermediate portion, and a PTO rear cover 3c for closing the opening at the rear end. An engine flywheel 6 is positioned at the foremost part in the front housing 1, and a driving shaft 8 connected to the engine flywheel 6 via a buffer joint 7 is provided in the front housing 1.

The traveling transmission mechanism includes a forward / reverse switching device 10, a high / low speed switching device 13, a main transmission device 16 and an auxiliary transmission device 19 connected in series. The forward / reverse switching device 10 is disposed between the support wall 1a and the first bearing frame 4 between the driving shaft 8 and the driven shaft 9 disposed therebelow. The high / low speed switching device 13 is disposed on the extended line of the driven shaft 9 between the first bearing frame 4 and the second bearing frame 5, and is connected to the driven shaft 9 and the driving shaft 8. It arrange | positions between the hollow driven shafts 12 arrange | positioned on the extension line.
The main transmission 16 is arranged on the extension line of the driven shaft 12 and is in the front half of the intermediate housing 2 between the driven shaft 15 and the driven shaft 15 arranged on the extension line of the hollow drive shaft 14 connected to the driven shaft 15. It is arranged.
The auxiliary transmission 19 includes a hollow counter shaft 17 disposed in the rear half of the intermediate housing 2 between the driven shaft 15 and the propeller shaft 18 disposed on the extension line thereof, and disposed on the extension line of the drive shaft 14. It is configured as follows.

  The rear end of the propeller shaft 18 extends into the rear housing 3 and includes a small bevel gear 21 that meshes with an input bevel gear 20 of a differential for left and right rear wheels (not shown). A front wheel driving force take-out case 22 is attached to the bottom of the intermediate housing 2, and the propeller shaft 18 is connected to a front wheel driving force take-out shaft 23 supported by the take-out case 22 via a front wheel driving clutch 24. Yes.

  The transmission mechanism of the PTO system is such that a transmission shaft 25 penetrating the hollow driven shaft 12, the drive shaft 14 and the counter shaft 17 is connected to the driving shaft 8 at its front end and connected to the rear end of the transmission shaft 25. A PTO clutch 28 is disposed between a transmission shaft 26 provided in the rear housing 3 and another clutch shaft 27 disposed on the extension line thereof. A PTO transmission 30 having two speeds is disposed between the clutch shaft 27 and a PTO shaft 29 that is disposed below the clutch shaft 27 and extends rearward from the PTO rear cover 3c. On the upper surface of the rear housing 3, a hydraulic lift device 33 including left and right lift arms 33 a for raising and lowering a working machine (not shown) driven by the PTO shaft 29 is installed.

In the forward / reverse switching device 10, two gears 34 and 35 are loosely arranged on the driving shaft 8, and two gears 36 and 37 are fixed on the driven shaft 9. Of these, the gears 34 and 37 are directly meshed, and the gears 35 and 37 are meshed via an intermediate idler gear (not shown).
A forward hydraulic clutch 40F and a reverse hydraulic clutch 40R are disposed on the driving shaft 8 between the gears 34 and 35.

  Each of the forward hydraulic clutch 40F and the reverse hydraulic clutch 40R is energized by supporting a plurality of friction elements arranged alternately on gears and clutch cylinders (not shown) in a slidable and relatively non-rotatable manner. The piston is moved to the direction of the friction element by the action of hydraulic pressure, and is configured as a known friction multi-plate type that obtains clutch engagement. Then, by engaging the forward hydraulic clutch 40F and coupling the gear 34 to the driving shaft 8, the driven shaft 9 is rotated in the vehicle forward direction, and the reverse hydraulic clutch 40R is engaged and the gear 35 is moved to the driving shaft 8. As a result, the driven shaft 9 is rotated in the vehicle reverse direction.

  In the high / low speed switching device 13, two gears 43 and 44 are loosely arranged on the drive shaft 11 connected to the driven shaft 9 by using the boss portion of the gear 36, and on the driven shaft 12. Two gears 45 and 46 are fixed to each other. The gears 43 and 44 and the gears 45 and 46 are meshed with each other. On the drive shaft 11, a high speed hydraulic clutch 48 </ b> H and a low speed hydraulic clutch 48 </ b> L that share a clutch cylinder fixed on the drive shaft 11 are disposed between the gears 43 and 44.

  Each high-speed hydraulic clutch 48H supports a plurality of friction elements arranged alternately on the boss portion of the gear 43 and the clutch cylinder so as to be slidable and relatively non-rotatable, and the urged piston is hydraulically actuated. It is constituted by a known friction multi-plate type that moves in the direction of the friction element to obtain clutch engagement. In particular, the low speed hydraulic clutch 48L supports a plurality of friction elements arranged alternately on the boss portion of the gear 44 and the clutch cylinder so as to be slidable and relatively non-rotatable. This is a so-called spring hydraulic oil type friction multi-plate clutch that is moved in the direction of the friction element by the urging force of the disc spring to obtain clutch engagement. A known technique can be used for the structure of the spring hydraulic oil type friction multi-plate clutch, and detailed description of the structure is omitted.

  In the main transmission 16, four gears 49, 50, 51, 52 are fixed on the drive shaft 14, and four gears 53, 54, 55, 56 are loosely fitted on the driven shaft 15. ing. Corresponding gears among these gears are engaged, and two synchronous clutches 57 and 58 are disposed on the driven shaft 15 between the gears 53 and 54 and between the gears 55 and 56, and the gears 53, 54 and 55 are arranged. -It is configured to obtain a 4-speed shift by selectively coupling 56 to the driven shaft 15.

  In the auxiliary transmission device 19, the counter shaft 17 is speed-reduced and connected to the driven shaft 15 through a train of reduction gears 59 and 60, and two gears 61 and 62 are fixed on the counter shaft 17. Among these, the gear 64 connected via the reduction gear mechanism 63 is disposed outside the counter shaft 17 with respect to the gear 62 on the small diameter side. A shift gear 65 that can selectively mesh with the gears 64 and 62 is loosely fitted on the propeller shaft 18, and the position where the shift gear 65 is coupled to the propeller shaft 18 and the propeller shaft 18 are A double clutch 66 that is operated to a position that is directly connected to the driven shaft 15 is provided. By configuring in this way, the auxiliary transmission 19 is 1st speed by meshing the gears 64 and 65, 2nd speed by meshing the gears 62 and 65, 3rd speed by meshing the gear 66 with the propeller shaft 18, and By directly coupling the propeller shaft 18 to the driven shaft 15, each of the four speeds is selectively caused to the propeller shaft 18.

Next, the structure of the rear part of the tractor body will be described.
As shown in FIG. 2, the rear end portion of the transmission shaft 26 is rotatably supported by a support wall portion 32 provided in the middle of the rear housing 3a, and the clutch shaft 27 is a shaft support hole at the rear end of the transmission shaft 26. And the PTO rear cover 3c are rotatably supported at both ends. The PTO shaft 29 is formed with a spline 29a at the rear end for connection to a universal joint (not shown) for mounting the work machine.

  The PTO clutch 28 has a plurality of friction elements that are slidable relative to a rotary boss 28c fixedly installed on the rear end portion of the transmission shaft 26 and a clutch housing 28a fixedly arranged on the front end portion of the clutch shaft 27. It is configured to support non-rotatability. In the clutch housing 28a, a piston 28b is urged in a backward direction by a return spring 28d, and the PTO clutch 28 moves forward by moving the piston 28b by the action of hydraulic pressure so that the friction elements are pressed against each other to engage the clutch. This is a so-called friction multi-plate hydraulic clutch.

  In the clutch shaft 27, a hydraulic oil passage 81 opened behind the piston 28b is formed in parallel with the shaft center with its base end opened on the back surface of the clutch shaft 27. The clutch shaft 27 is provided with a lubricating oil passage 82 for supplying lubricating oil to the friction element portion of the PTO clutch 28. The passage 82 has an open end into the clutch housing 28a in a clutch disengaged state. In this case, the piston is blocked by the piston b and is opened by an oil hole 85 formed in the piston b when the piston b is advanced.

  The lubricating oil passage 82 is configured to supply lubricating oil to the support portion at the front end of the clutch shaft 27, and the base end of the passage 82 is an annular oil chamber formed between the clutch shaft 27 and the PTO rear cover 3c. The lubricating oil port 83 provided in the PTO rear cover 3c is connected to the oil chamber 84 so as to open to the oil chamber 84.

As shown in FIG. 2, the PTO transmission 30 includes two gears 27a and 27b provided so as to rotate integrally on the clutch shaft 27 and a gear 68 · provided free to rotate on the PTO shaft 29. 69 is meshed with each other. A shifter sleeve 70 is provided on the PTO shaft 29 so as not to be relatively rotatable and slidable in the axial direction. A shifter fork 71 is engaged with the shifter sleeve 70. The shifter sleeve 70 has spline teeth on its inner peripheral surface that can mesh with teeth 68a and 69a formed on the bosses of the gears 68 and 69, respectively.
With such a configuration, the shifter sleeve 70 is selectively slid and displaced by the shifter fork 71, and the gear 68 is coupled to the PTO shaft 29 by engaging with the tooth portion 68a. By combining the gear 68 with the PTO shaft 29, a second speed gear ratio can be selectively obtained at the PTO shaft 29.

As shown in FIG. 3, when the PTO clutch 28 is disengaged, the PTO clutch 28 is disengaged in order to quickly stop the inertial rotation of the driven side of the clutch 28 and to prevent the frictional elements from being swung between the friction elements. A PTO brake mechanism 90 for braking the clutch housing 28a is provided.
That is, a brake support shaft 95 parallel to the transmission shaft 26 is provided on both ends of the support wall portion 32 and the PTO rear cover 3c, and the brake shoe 97 is attached to the brake support shaft 95 on the outer peripheral surface of the clutch housing 28a. On the other hand, it is supported so as to be rotatable in the direction of contact and separation. The brake shoe 97 is wound around the brake support shaft 95, and is rotated in a direction away from the clutch housing 28a by a torque spring 96 having one end engaged with the brake shoe 97 and the other end engaged with the upper surface of the support wall 32. It is energized.

  A hydraulic cylinder 92 whose outer end is sealed is inserted into a hole formed in one side wall of the rear housing 3 in an oil-tight manner, and is fixed to the one side wall by a bolt 76 and is fitted to the hydraulic cylinder 92. The piston 91 is brought into contact with the free end of the brake shoe 97 at its tip. The piston 91 is moved and urged in a backward direction by a spring 93 provided in the hydraulic cylinder 92, and an oil chamber 94 for advancing the piston 91 is provided in the hydraulic cylinder 92 to act on the oil chamber 94. The piston 91 is advanced by hydraulic pressure, and the brake shoe 97 is pressed against the clutch housing 28a to obtain the operation of the PTO brake mechanism 90. An oil passage 78 that opens to the oil chamber 94 is formed on one side wall of the rear housing 3, and hydraulic pressure is applied to the oil chamber 94 via the oil passage 78 when the PTO clutch 28 is disengaged.

As shown in FIG. 3, a fork shaft 73 parallel to the PTO shaft 29 is slidably supported at both ends by the support wall portion 32 and the PTO rear cover 3c. A shift fork 71 in the transmission 30 is fixedly supported. Each of the fork shafts 73 is engaged with an arm 74 attached to the inner end of a rotary operation shaft 75 penetrating the side wall of the rear housing 3.
The rotation operation shaft 75 is connected to an operation lever (not shown) at the outer end thereof, and the shift fork 71 is slid and displaced together with the fork shaft 73 by the rotation operation of the rotation operation shaft 75, so that the shift sleeve 70 is required. To get the displacement.

  As shown in FIGS. 4 and 8, the fork shaft 73 is provided with a detent mechanism 99 that holds the sliding displacement of the fork shaft 73 when the PTO clutch 28 is engaged. The detent mechanism 99 is formed with two ring-shaped grooves 73a and 73b around the fork shaft 73, and a ball 99a selectively facing one of the grooves 73a and 73b by a spring 99c on the rod 99b. It is energized and provided in the PTO rear cover 3c.

  The base end of the spring 99c is received by a bolt 99e screwed in the hole of the PTO rear cover 3c and covered. The ball 99a is pressed against the rod 99b by the biasing force of the spring 99c. As a result, the ball 99a is fitted into one of the grooves 73a and 73b so that the fork shaft 73 is not easily slid and displaced. Therefore, the fork shaft 73 is slid by the operator operating the PTO speed change lever and is restrained to the first speed position or the second speed position by the detent mechanism 99.

As shown in FIGS. 5, 6, and 7, the PTO rear cover 3 c is integrally provided with a PTO valve 72, and the PTO valve 72 is disposed laterally (in the left-right direction) above the PTO rear cover 3 c. A modulation type relief valve 67 and an electromagnetic directional switching valve 47 disposed on the side of the modulation type relief valve 67 at the upper part of the PTO rear cover 3c.
Further, as shown in FIG. 5, an inspection window 77 is formed on the PTO rear cover 3c and at a side position of the PTO shaft 29, and the operation filled in the housing (mission case) from the inspection window 77 is formed. The amount of oil (lubricating oil) can be checked. The inspection window 77 is composed of circular glasses 77a and 77b arranged in parallel up and down. If the oil level is visible on the lower glass 77b, it is necessary to add hydraulic oil to the upper glass 77a. If the oil level is visible, the oil amount is appropriate and the oil amount can be easily confirmed. In this way, the inspection window 77 can be seen from the rear of the machine body, the work of checking the oil amount by inserting the oil inspection rod and the like and removing it can be eliminated, and the oil amount can be easily checked. . However, the inspection window may have a configuration in which a line indicating an appropriate amount, a shortage line, or the like is provided in the inspection window as a long inspection window, and the shape and number are not limited.

As shown in FIGS. 7, 9, and 10, the electromagnetic direction switching valve 47 is mounted on the PTO rear cover 3 c in a vertical direction (vertical direction), and the PTO rear cover 3 c at the vertical center of the electromagnetic direction switching valve 47. The oil passage 103 formed in the above is communicated with the hydraulic cylinder 92 of the PTO brake mechanism 90 through the port 104.
An oil passage 112 is formed in the lower portion of the electromagnetic direction switching valve 47 in the forward direction. The oil passage 112 is supplied with pressure oil from a hydraulic pump as a pump port, and below the electromagnetic direction switching valve 47 is an oil passage. A passage 113 is formed, and the oil passage 113 communicates with the inside of the housing.
An oil passage 101 is formed in the left and right direction above the electromagnetic direction switching valve 47, and the oil passage 101 communicates with a modulated relief valve 67 described later.
With such an electromagnetic direction switching valve 47 and an oil path configuration communicating with the electromagnetic direction switching valve 47, the oil path communicating with the PTO clutch 28 or the PTO brake mechanism 90 can be switched.

  As described above, the PTO valve 72 is provided integrally with the PTO rear cover 3c, and the oil passage and the hydraulic port for communicating the PTO valve 72 and the PTO clutch 28 are formed inside the PTO rear cover. Modularization can be realized. In other words, specifications can be easily changed by attaching and removing the PTO rear cover equipped with a hydraulic PTO clutch and the PTO rear cover equipped with a mechanical switching device, and the number of parts can be reduced using the same housing. It is. In addition, work can be performed from the rear of the machine body, and maintenance can be easily performed with less detachment and disassembly of surrounding equipment. The PTO valve 72 for switching control can be disposed close to the PTO clutch 28, the oil passage can be shortened, the hydraulic loss is reduced, the responsiveness is increased, and the stable. Hydraulic control is possible.

Next, the hydraulic circuit of the tractor will be described with reference to FIG.
As shown in FIG. 11, hydraulic pumps 120, 136, and 137 driven by the engine 6 are provided, and the hydraulic pump 120 supplies hydraulic pressure from the circuit 140 to the hydraulic clutches 40 F and 40 R of the forward / reverse switching device 10. Like to do.
The hydraulic pump 136 supplies hydraulic pressure to the switching valve of the power steering mechanism 139 for assisting turning of the left and right front wheels, and the excess oil is supplied from the oil passage 142 via the ON / OFF valve 144 to the front wheel drive switching clutch 24 and the auxiliary wheel. The PTO clutch 28 and the PTO brake mechanism 90 are supplied via a high / low speed switching clutch 48 and a PTO valve 72 for shifting. The hydraulic pump 137 supplies hydraulic pressure to a lifting cylinder attached to the tractor and a drive circuit for an external actuator.
From the oil passage 142, the lubricating oil can be supplied to the friction plate portions of the high / low speed switching clutch 48 and the PTO clutch 28 via a relief valve.

  The pressure oil sent to the oil passage 142 is sent to the oil passage 112 of the PTO valve 72, and when the PTO shaft 29 is not driven, the electromagnetic direction switching valve 47 is switched and sent to the PTO brake mechanism 90. The piston is extended, and the brake shoe 97 is brought into contact with the outer peripheral surface of the clutch housing 28a for braking to prevent inertial rotation. When the PTO lever is turned to the “on” side or the PTO switch is turned on, the solenoid of the electromagnetic direction switching valve 47 is operated to switch the pressure oil to the modulated relief valve 67, and the PTO clutch 28 can be operated to transmit power to the PTO shaft 29 and drive it.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic partially developed longitudinal sectional view showing an overall configuration of a tractor transmission mechanism according to an embodiment of the present invention. The longitudinal side view of the rear part of the body of a tractor. Similarly cross-sectional front view. FIG. Similarly front view. AA arrow sectional drawing in FIG. BB arrow sectional drawing in FIG. FF arrow sectional drawing in FIG. CC sectional view taken on the line in FIG. DD sectional view taken on the line in FIG. The hydraulic circuit diagram of a tractor.

Explanation of symbols

3 Rear housing 3c PTO rear cover 28 PTO clutch 47 Electromagnetic direction switching valve 67 Modulated relief valve 72 PTO valve 77 Inspection window 90 PTO brake mechanism 101, 102, 103, 106, 112, 113 Oil passage 104 Port

Claims (4)

A power take-out device for a work vehicle in which a PTO rear cover is attached to a rear end portion of a rear housing of an airframe,
A power take-out device for a work vehicle, wherein a PTO valve is provided integrally with the PTO rear cover, and an oil passage and a hydraulic port for communicating the PTO valve and a PTO clutch are formed inside the PTO rear cover. A valve for oil pressure setting is arranged on the machine body side, pressure oil supplied from the valve is supplied to the PTO valve, and pressure oil is supplied to the PTO clutch and the PTO brake by the PTO valve. The power take-out device for a work vehicle according to claim 1. The power take-out device for a work vehicle according to claim 1 or 2, wherein the PTO valve is disposed on an upper part of a PTO rear cover. The power take-out device for a work vehicle according to claim 1, wherein an oil inspection window is provided in the PTO rear cover.

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