JP2005254889A - Pto transmission device of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To excellently prevent the inertial rotation of a PTO shaft generated when uncoupling a clutch to shut off the power transmission to the PTO shaft by a simple means. <P>SOLUTION: A PTO transmission device has a transmission body to transmit the engine output and a brake disk to prevent the co-rotation on a PTO shaft, and comprises a brake spring to be interposed between the transmission body and the brake disk, foldable front and rear links to connect the transmission body to the brake disk, and a weight interposed between the front and rear links. The brake disk is pressed against a friction body by the brake spring force when the PTO shaft is rotated at a low speed, and the brake disk is separated from the friction body by the centrifugal effect of the weight when the PTO shaft is rotated at a high speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a PTO transmission device for a work vehicle such as a tractor that performs farming work or earthwork work by installing a farm work machine or earthworking work machine, for example.

  Conventionally, there is a drive structure that transmits the output from the engine to the PTO shaft via a PTO clutch, etc., and when the transmission of power to the PTO shaft is interrupted by disconnecting the PTO clutch, etc., the PTO shaft rotates with inertia. As one of the means for preventing, there is a technique in which an inertia brake is arranged in a transmission path from the PTO clutch to the PTO shaft, and the PTO clutch and the inertia brake are connected by a link mechanism. (For example, see Patent Document 1)

Japanese Patent Laid-Open No. 10-24746

  However, in the case of the conventional means as described above, since the PTO clutch and the inertia brake are located at separate positions, not only the structure becomes complicated but also the connection of a link or the like is required, so that the assembling work becomes difficult.

  For this reason, there are means such as tightening the PTO shaft and the transmission shaft connected to the PTO shaft by a leaf spring, but in this case, the power loss is large, and the power loss is converted into heat energy, which causes an increase in the oil temperature. There is.

  Therefore, the present invention is provided with a transmission body for transmitting engine output and a brake plate for preventing swirling on the PTO shaft, and a brake spring interposed between the transmission body and the brake plate, and the transmission body and the brake plate are connected to each other. A flexible front / rear link and a weight body interposed between the front / rear links are provided so that the brake plate is pressed against the friction body by the brake spring force when the PTO shaft is rotated at a low speed, and the weight body is operated when the PTO shaft is rotated at a high speed. The brake plate is provided so as to be separated from the friction body by the centrifugal action.

  Further, a notch is formed in the disk body that restricts the rotation of the PTO shaft, and a reverse rotation preventing claw is engaged with the notch to prevent the reverse rotation of the PTO shaft.

  Thus, according to the present invention, the PTO shaft is provided with a transmission body for transmitting engine output and a brake plate for preventing rotation, and a brake spring interposed between the transmission body and the brake plate, the transmission body and the brake A flexible front / rear link for connecting the plate and a weight body interposed between the front / rear links are provided, and the brake plate is pressed against the friction body by the brake spring force when the PTO shaft is rotated at a low speed. When rotating, the brake plate is separated from the friction body by the centrifugal action of the weight body, so that the brake plate and the front / rear link can be easily incorporated into the PTO shaft, and when the transmission of power to the PTO shaft is interrupted, the brake plate must be securely This prevents the PTO shaft from rotating and eliminates power loss due to friction of the brake plate during rotation of the PTO shaft and enables efficient rotation of the PTO shaft. It is.

  In addition, a notch is formed in the disk body that restricts the rotation of the PTO shaft, and a claw for preventing reverse rotation is engaged with the notch to prevent reverse rotation of the PTO shaft. Compared to the conventional structure that prevents the reverse rotation by inserting a pin biased by a spring into the groove, there is no need for lubrication for the pin, and the structure is simplified and the inertia rotation (reverse rotation) of the PTO shaft is ensured. It is possible to prevent and improve workability.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of a tractor. In the figure, reference numeral 1 denotes a tractor which is a work vehicle for agriculture, etc., and left and right front wheels 4 and 4 are installed on both sides of a bonnet 3 in which an engine 2 is installed. A round steering handle 6 is provided in a driving cabin 5 behind the vehicle, a driver's seat 7 is disposed behind the handle 6, and left and right rear wheels 8 and 8 are installed on both sides of the driver's seat 7.

  As shown in FIG. 2, the traveling drive system 10 of the transmission case 9 for transmitting the output of the engine 2 includes a main clutch part 11, a forward / reverse switching part 12b for switching to forward / reverse, a high / low speed switching part 13 for switching to high / low speed, A main transmission unit 14 that switches the traveling speed to four stages, an auxiliary transmission unit 15, a differential mechanism 18 that connects the rear wheel output shaft 17 to the traveling output shaft 16 of the auxiliary transmission unit 15, and a PTO drive shaft 19 from the engine 2. A PTO shaft 20 connected to the tractor 1 is provided, and the power of the PTO shaft 20 is transmitted to various working machines to be mounted on the tractor 1 to perform various farming operations by these working machines.

2, 3, and 4, the PTO shaft 20 is linked to the PTO drive shaft 19 through transmission gears 21 and 22, and the bearings 23 and 24 are connected to the inner end and the middle of the PTO shaft 20. The transmission gear 22 is spline-fitted to the spline portion 20a between the bearings 23 and 24 of the PTO shaft 20 by being rotatably supported by the transmission case 9.

  Further, a ring-shaped brake plate 26 having a friction plate 25 is fitted on the inner end side of the PTO shaft 20, and the brake plate 26 and the transmission gear 22 are connected by a plurality of sets of front and rear links 27 and 28 that can be bent. Thus, one end side of the front link 27 is swingable through the pivot 29 on the side opposite to the friction plate 25 of the brake plate 26 and one end side of the rear link 28 is swingable through the pivot 30 on the opposite side of the transmission gear 22. At the same time, the other ends of the front and rear links 27 and 28 are connected to the same shaft 31 so that they can be bent (folded), and a weight body 32 is attached to the central shaft 31 of the front and rear links 27 and 28 having substantially the same length. Yes.

  A brake spring 33, which is a compression spring, is interposed between the brake plate 26 on the outer periphery of the PTO shaft 20 and the transmission gear 22, and the friction plate 25 of the brake plate 26 is pressed by the pressing force of the spring 33 when the PTO shaft 23 rotates zero or low. Is pressed against the inner wall surface 9a of the case outside the bear link 23 to prevent inertial rotation of the main clutch portion 11 when the main clutch is disengaged (rotation), while FIG. As shown, the front and rear links 27 and 28 are contracted by the centrifugal force of the weight body 32 rotating around the shaft 20, and the friction plate 25 of the brake plate 26 is separated from the inner wall surface 9a of the case. It is comprised so that rotation may be performed.

  As is clear from the above, the brake spring 33 is provided on the PTO shaft 20 with the gear 22 serving as a transmission for transmitting the output of the engine 2 and the brake plate 26 for preventing the rotation, and is interposed between the transmission 22 and the brake plate 26. And bendable front and rear links 27 and 28 for connecting the transmission 22 and the brake plate 26, and a weight body 32 interposed between the front and rear links 27 and 28, and a brake spring when the PTO shaft 20 rotates at a low speed. The brake plate 26 is pressed against the case inner wall surface 9a, which is a friction body, by force, and the brake plate 26 is separated from the case inner wall surface 9a by the centrifugal action of the weight body 32 when the PTO shaft 20 rotates at high speed. 26, front and rear links 27 and 28, etc. are easily incorporated into the PTO shaft 20, and when the power transmission to the PTO shaft 20 is interrupted, the brake plate 26 is acted on securely. While preventing entanglement around the O axis 20, is capable of rotating the PTO shaft 20 to permit rotation of the efficiency good PTO shaft 20 by eliminating the power loss due to the friction of the brake plate 26.

  As shown in FIGS. 5 to 7, a PTO clutch mechanism 34 a can be incorporated in the middle of the PTO drive shaft 19, and an input shaft 19 a that connects the PTO drive shaft 19 to the main clutch portion 11 and a transmission gear 21. The PTO clutch shaft 19b is connected to the clutch body 36. The clutch member 34 of the input shaft 19a and the clutch body 36 of the clutch piston 35 form a PTO clutch 37, and the brake body is rotatably connected to the clutch body 36. 38 and the clutch body 36 are formed, and when the clutch piston 35 is slid by the operating shaft from the oil passage 40 of the clutch shaft 19b, the PTO clutch 37 is inserted and the brake 39 is set to the non-braking state. On the other hand, when the PTO clutch 37 in which the clutch piston 35 moves backward by the return spring 41 or the like is disengaged, 9 as the braking state, the clutch member 36 and the brake member 38 is integral, at the time of inertial rotation of the clutch member 36 to the state turns with the brake member 38.

  The one end cylindrical portion 38a of the brake body 38 is formed with a notch 43 for engaging the tip claw portion 42a of the reverse rotation preventing claw 42 to prevent reverse rotation. The tip of a leaf spring 46 that is fixed to the prevention claw 42 is pressed against the inner wall 45 of the transmission case 9 that surrounds the outside of the cylindrical portion 38 a, and the claw portion 42 a of the prevention claw 42 is always fixed by the leaf spring 46. When the notch 43 and the claw portion 42a are engaged with each other, the cylinder portion 38a (clutch shaft 19b) is allowed to rotate in one direction a and the reverse rotation b is prevented. It is configured to do.

  As described above, when the PTO clutch 37 is disengaged, the PTO brake 39 is in the braking state, and the brake body 38 is rotated (reversely rotated) b by the inertial force, this rotation is achieved by the engagement of the prevention pawl 42. And the inertial rotation of the PTO shaft 20 is prevented.

  When the PTO clutch 37 is disconnected and the drive input unit on the various work machines side and the PTO shaft 20 are connected, the forward rotation (spinning) a enables easy connection. When the clutch 37 is disengaged, the workability can be improved by appropriately allowing the rotation in the direction opposite to the driving direction.

  As is clear from the above, a notch is formed in the brake body 38 which is a disc body that restricts the rotation of the PTO shaft 20, and the reverse rotation preventing claw 42 is engaged with the notch 43, so that the reverse rotation of the PTO shaft 20 is performed. Compared to the conventional structure that prevents the reverse rotation by inserting a pin biased by a spring into the engagement groove formed in the brake body 38 which is a disc body, for example, there is no need for lubrication for the pin, By simplifying the structure, it is possible to reliably prevent inertia rotation (reverse rotation) b of the PTO shaft 20 and improve workability.

The whole tractor side view. Explanatory drawing of a PTO shaft drive system. The braking explanatory drawing of a PTO brake board. Non-braking explanatory drawing of a PTO brake plate. Explanatory drawing of a PTO clutch mechanism. Explanatory drawing of a reverse rotation prevention nail | claw part. The perspective explanatory drawing of a reverse rotation prevention nail | claw part.

Explanation of symbols

2 Engine 9a Case inner wall (friction body)
20 PTO shaft 22 Gear (transmission element)
26 Brake plate 27 Front link 28 Rear link 32 Weight body 33 Brake spring 38 Brake body (disc body)
42 nails 43 notches

Claims (2)

  The PTO shaft is equipped with a transmission body that transmits engine output and a brake plate that prevents rotation, a brake spring that is interposed between the transmission body and the brake plate, and a bendable structure that connects the transmission body and the brake plate. A front / rear link and a weight body interposed between the front / rear links are provided, and the brake plate is pressed against the friction body by the brake spring force when the PTO shaft is rotated at a low speed, and the brake is braked by the centrifugal action of the weight body when the PTO shaft is rotated at a high speed. A PTO transmission device for a work vehicle, characterized in that a plate is provided so as to be separated from a friction body.   2. A PTO for a work vehicle according to claim 1, wherein a notch is formed in a disk body that restricts rotation of the PTO shaft, and a claw for preventing reverse rotation is engaged with the notch to prevent reverse rotation of the PTO shaft. Transmission device.

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