JP2009296900A - Riding type lawn mower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a riding type lawn mower in which a degree for reducing a mower-lifting or lowering action range is reduced with a shaft cover for covering a transmission shaft having a universal joint and which covers the whole periphery of the transmission shaft including a universal joint portion. <P>SOLUTION: Provided is the riding type lawn mower characterized in that the shaft cover 5 covering the outer periphery of a transmission shaft 3 for transmitting a driving force from the side of a travel machine frame 1 to a mower 4 comprises the first cover portion 51 mounted on the side of the travel machine frame 1 and the second cover portion 52 mounted on the side of the mower 4. The first cover portion 51 has a cylindrical cover portion 51a for covering the shaft portion of the transmission shaft 3 excluded from the universal joint portion 30 on the side of the mower 4, and the second cover portion 52 is formed to cover the universal joint portion 30 on the side of the mower 4 and also cover the mower 4 side end portion of the first cover portion 51. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement of a riding mower used for cutting grass such as turf.

In the above-described riding type mower, the mower suspended from the traveling machine body is configured to be driven from the traveling machine body via the transmission shaft, and the transmission shaft as a drive structure portion thereof is configured. In some cases, it may be desired to provide a protective cover. Among these riding-type mowers, the mid-mount type with a mower positioned between the front and rear wheels to facilitate turning in a small turn makes the transmission shaft hidden under the vehicle body. There is no protective cover for the transmission shaft in particular, and in the case of a front mount type with a mower provided on the front side of the traveling body, a cover is provided on the shaft transmission structure to the mower as described in [1] below. There is a thing of the provided structure.
[1] On the upper side of the transmission shaft that transmits power from the traveling machine body side to the mower side, a channel-shaped fixed cover that covers the mower side universal joint of the transmission shaft is provided near the mower side gear case, and the mower is suspended and supported. A structure in which the upper side of the transmission shaft is covered with a channel-shaped transmission cover pivotally supported at one end on the lift link (see Patent Document 1).

Moreover, as a technique that merely covers the transmission shaft portion of the structure having the universal joint in the shaft intermediate portion, it is not used in the riding type mower, but the structure described in [2] below is also used. is there.
[2] A structure in which the transmission shaft portion is covered with a cylindrical cover and the periphery of the universal joint is covered with a soft bag-like cover (see Patent Document 2).

JP-A-11-9050 (paragraphs [0020], [0021], FIG. 2, FIG. 3) JP-A-8-20251 (paragraph [0019], FIG. 1, FIG. 2, FIG. 4)

Since the transmission shaft for transmitting the driving force to the mower is one in which the mower itself moves up and down, it is essential to provide a universal joint at the shaft intermediate portion.
When a cover is provided to cover the shaft portion provided with such a universal joint, generally, as described in Patent Document 2, unless a precondition of a transmission structure to a mower that is moved up and down is considered. In addition, it is conceivable to adopt a means such as a configuration in which the periphery of the universal joint is covered with a flexible cover having a large inner diameter that does not hinder its movement.
However, the universal joint itself has a considerably larger rotation diameter than the transmission shaft portion, and as the refraction angle range of the universal joint accompanying the raising / lowering operation of the mower increases, the rotation locus of the universal joint in the cover increases. The diameter becomes large, the inner diameter of the cover covering the universal joint becomes considerably large, and the cover itself is enlarged. Therefore, if a cover with a large diameter is positioned on the mower deck, the range in which the mower can be lifted is reduced by the size of the cover, and the mower liftable range is limited. However, there is a problem that it is difficult to lift the mower suspended from the traveling body sufficiently large.

Therefore, as described in Patent Document 1, a universal joint on the mower side of the transmission shaft is covered with a channel-shaped fixed cover, and the lower end open side of the fixed cover is fixed to the mower deck to cover the entire circumference of the universal joint. The transmission shaft portion is configured to cover only the upper surface side with a channel-shaped transmission cover. Such a configuration is advantageous in that the height of the fixed cover on the mower deck can be kept relatively low compared to the case where the universal joint portion is covered with a cover that covers the entire circumference of the universal joint portion.
However, in this structure, the end of the transmission cover on the mower side is provided so as to overlap the upper side of the fixed cover, and the transmission cover swings and displaces on the upper side of the fixed cover as the vertical position of the mower changes. A vertical height is required to allow this. Therefore, if you want to move the mower up and down on the lower side of the traveling machine body, the thickness of the transmission cover that overlaps the upper side of the fixed cover and that the transmission cover swings and displaces on the upper side of the fixed cover as the mower moves up and down. The range in which the mower can be lifted is reduced by the vertical height to allow.
In addition, in this structure, since the transmission case has a channel shape and is open at the bottom, there is a problem that it cannot be used when it is desired to cover the entire circumference of the transmission shaft due to a problem in standards or the like.

  The object of the present invention is to construct a shaft cover that covers a transmission shaft with a universal joint for transmitting a driving force to a mower suspended from a traveling machine body so as to be able to move up and down. It is to provide a shaft cover that can reduce the degree of reduction as much as possible and can cover the entire circumference of the transmission shaft including the universal joint portion.

[Solution 1]
The technical means of the present invention taken in order to solve the above-mentioned problem is suspended from the traveling machine body so as to be able to be raised and lowered, and the driving force is transmitted from the traveling machine body via the transmission shaft. In a riding mower equipped with a mower,
The transmission shaft includes a universal joint connected to each of the output shaft on the traveling machine body and the input shaft on the mower side, and is configured to be refracted at each end, and the outer periphery of the transmission shaft is With a covering shaft cover,
The shaft cover is composed of a combination of a first cover portion mounted on the traveling machine body side and a second cover portion mounted on the mower side,
The first cover portion includes a cylindrical cover portion that covers the shaft portion of the transmission shaft at a position separated from the universal joint portion on the mower side,
The second cover portion is configured to cover the mower side universal joint portion and to cover the mower side end portion of the first cover portion.

[Action and effect]
As described above, the riding mower of the present invention according to the solution 1 has the following actions and effects.
In other words, the second cover portion mounted on the mower side of the shaft cover is configured to cover the mower side universal joint portion and to cover the mower side end portion of the first cover portion. For this reason, compared to the case where the entire circumference of the universal joint portion on the mower side is covered with a cover or the like, there is no need for a cover portion that covers at least the lower side of the universal joint portion on the mower side. Can be placed as close to the mower deck as possible.
The mower side end portion of the first cover portion does not need to cover the universal joint portion on the mower side, and has a relatively small diameter formed in a cylindrical shape covering the transmission shaft portion. The second cover portion that covers the mower side end portion of the first cover portion does not need to be formed large as in the case of covering the universal joint portion even if the mower side end portion of the first cover portion is positioned inside.
The first cover portion includes a cylindrical cover portion that covers the shaft portion of the transmission shaft at a position away from the universal joint portion on the mower side, and the universal joint portion on the mower side cooperates with the second cover portion and the mower deck. The transmission shaft is provided in a state where the entire circumference is covered.

As a result, the shaft cover of the transmission shaft with a universal joint for transmitting the driving force to the mower suspended to be able to move up and down on the traveling machine body is reduced as much as possible to reduce the range of the mower lifting operation by the presence of the shaft cover. There is an advantage that it can be provided in a reduced state.
Further, there is an advantage that a shaft cover that can cover the entire circumference of the transmission shaft including the universal joint portion can be configured in a compact manner.

[Solution 2]
The second solving means in the riding mower of the present invention is that the second cover portion is fixedly supported on the mower side as described in claim 2.

[Action and effect]
As described above, the riding mower of the present invention according to the solving means 2 has the following effects in addition to the same effects as the invention according to the solving means 1.
In other words, the second cover that covers the universal joint on the mower side is fixedly supported on the mower side, so that the degree of the shaft cover swinging due to vibrations caused by airframe travel is reduced, and the shaft cover is maintained in a stable posture. There are advantages you can do.

[Overall configuration of riding mower]
FIG. 1 shows the entire side surface of the riding mower according to the present invention, and FIG. 2 shows the entire plane. This riding-type mower includes a pair of left and right front wheels 11 configured as caster-type idler wheels on the front end side of the body frame 10, and a pair of left and right drive wheels on the rear end side of the body frame 10. A traveling machine body 1 is configured with a wheel 12, and a bar blade type mower 4 is suspended and supported between the front and rear wheels of the traveling machine body 1 so as to be movable up and down.

A driving unit 2 that houses a water-cooled diesel engine 21 in an engine bonnet 20 is disposed at the rear part of the traveling machine body 1 in the rear frame portion of the aircraft frame 10, and is operated in the front and rear intermediate parts of the traveling machine body 1. A seat 13 is provided.
A gate-shaped overturning protection frame 14 is erected and fixed substantially vertically at the rear of the driver seat 13. The fall protection frame 14 is configured to be foldable rearward around the fulcrum x1 at the upper and lower intermediate portions, and by folding the fall protection frame 14 when mowing around the trunk of the tree, the fall protection frame 14 is extended to a branch protruding. It is configured to work without being caught.
A step 15 located at the foot of the driver seat 13 is mounted and mounted on the front frame portion of the body frame 10, and fenders 16 are provided on the left and right sides of the driver seat 13.

Since the structure of the transmission system is well known, detailed description of the structure is omitted. However, the output of the engine 21 is input to the counter case 22 and branched into the traveling system and the working system, and the power of the traveling system is the counter case. 22 is input to a pair of left and right hydrostatic continuously variable transmissions (HST) (not shown) provided on both the left and right sides of the motor 22, and the shift output is transmitted to the left and right rear wheels 12 via the deceleration case 23. It has become so.
The hydrostatic continuously variable transmission that drives the left and right rear wheels 12 swings a pair of left and right traveling levers 17 that are arranged to swing back and forth on both sides of the driver's seat 13 separately. The left and right rear wheels 12 are independently steplessly shifted forward and backward, and from the neutral stop state shown in FIG. Pivot turn and spin turn can be arbitrarily performed by each different operation.

[Moore configuration]
The mower 4 has a structure supported by being suspended through a link mechanism 18 having a four-link structure. The link mechanism 18 is configured to be lifted / lowered by an expansion / contraction operation of a hydraulic cylinder 19 connected to a part of the link mechanism 18 to move the mower 4 up and down substantially in parallel.
The transmission of power to the mower 4 is performed from the PTO shaft 24, which is an output shaft from the traveling machine body 1 side, in which the power of the work system branched by the counter case 22 projects from the lower front surface of the counter case 22. The engine power is output forward and the engine power is axially transmitted to the mower 4 via the PTO shaft 24 and the transmission shaft 3.

  The mower 4 has a three-sided rotary blade 41L, 41C, 41R that is rotationally driven around the longitudinal axis inside a mower deck 40 that is opened downward, so that the central rotary blade 41C is slightly displaced forward. It has a triangular arrangement and is supported by a shaft when viewed. When the traveling machine body 1 moves straight, the left and right ends of the tip rotation trajectories of the adjacent rotary blades 41L, 41C, 41R partially overlap. Therefore, mowing without cutting is possible.

The mower deck 40 is configured as a flat deck whose top plate height is set to the same overall height, and the working power extracted from the PTO shaft 24 is transmitted to the center position of the upper surface of the mower deck 40. A bevel gear case 42 is provided.
In this bevel gear case 42, the rotational power in the horizontal direction transmitted via the transmission shaft 3 is converted into vertical axis rotation via an internal bevel gear mechanism (not shown), and the rotational shaft 43C of the central rotary blade 41C is converted. Is configured to communicate.
The central rotating shaft 43C and the rotating shafts 43L and 43R of the left and right rotating blades 41L and 41R are interlocked by winding belts 45 around transmission pulleys 44, 44 and 44 provided at the respective shaft ends. 41L, 41C, and 41R are rotationally driven at a constant speed in the same direction (clockwise in plan view).

The transmission pulleys 44, 44, 44 and the wound belt 45 are concealed while being sandwiched between the upper surface of the mower deck 40 by a belt cover 46 provided so as to cover them from above. .
As shown in FIG. 3, the belt cover 46 is formed with a cutout portion 46 </ b> C that avoids the location where the bevel gear case 42 exists and the location where the transmission shaft 3 exists. The right cover portion 46R and the left cover portion 46L are configured. Further, the belt 45 wound around the transmission pulleys 44, 44, 44 is also arranged at a position avoiding the rotation locus of the universal joint 30 provided at the mower side end of the transmission shaft 3.
Therefore, as shown in FIG. 4, the universal joint 30 on the mower side has the upper surface of the belt cover 46 even if the lower edge of the rotation locus is provided to some extent below the upper surface of the belt cover 46. In addition, contact with the inner belt 45 can be avoided.

  An idle wheel (anti-scal roller) 47 for overcoming obstacles is provided around the mower deck 40, and the ground surface and the raised portion are supported by the mower 4 supported by being suspended by the link mechanism 18 with the flexibility of moving upward. When one of the freewheels 47 rides on a raised portion or the like, the mower 4 is lifted relatively, and the mower deck 40 is prevented from directly contacting and scraping the ground. ing.

[Configuration of shaft cover]
As shown in FIGS. 4 and 5, the transmission shaft 3 for transmitting power from the PTO shaft 24 to the bevel gear case 42 is a cylindrical first shaft connected to the PTO shaft 24 via a universal joint 30. A portion 31 and a rod-shaped second shaft portion 32 connected to the input shaft 42 a of the bevel gear case 42 via the universal joint 30 are configured.
The cylindrical first shaft portion 31 is constituted by a spline tube having a spline portion 31a formed on the inner surface of the tube, and the rod-shaped second shaft portion 32 is constituted by a spline shaft having a spline portion 32a formed on the outer surface. Thus, by fitting the spline portions 31a and 32a to each other, the relative rotation is impossible and the axial length of the transmission shaft 3 is adjustable.

The shaft cover 5 for the transmission shaft 3 having the above-described structure is configured by a combination of a first cover portion 51 attached to the traveling machine body 1 side and a second cover portion 52 attached to the mower 4 side.
The first cover portion 51 includes a cylindrical cover portion 51a that covers the first shaft portion 31 and the shaft portion of the second shaft portion 32 that are out of the universal joint 30 portion on the mower 4 side, and the cylindrical cover portion. At the end of the traveling machine body 1 side of 51a, a cover part 51b connected so as to cover the universal joint 30 part on the traveling machine body 1 side is provided. The cover 51b has an open end fixed to the wall of the counter case 22 of the traveling machine body 1. A posture of the end portion of the cylindrical cover portion 51 a is regulated by a collar member 51 c for maintaining a space provided between the end portion of the first cover portion 31 and the vicinity of the end portion of the mower side.

As shown in FIGS. 3 and 6, the second cover portion 52 is configured by a channel-shaped member having an open lower end side, and both lateral side portions thereof are rising edges of the belt cover 46 on the mower deck 40. The portion 46a is connected by a bolt / nut 53.
Therefore, the second cover part 52 is configured to cover the universal joint 30 part on the mower 4 side from the upper side in the mounting posture and to cover the mower side end part of the first cover part 51 from the upper side. .

As shown in FIG. 4, the shaft cover 5 configured as described above surrounds the outer periphery of the transmission shaft 3 so that the transmission shaft 3 is not exposed to the outside even when the mower 4 is moved to the lower limit and the upper limit. ing.
That is, the mower side end portion (front end side) of the first cover portion 51 generally swings around the refraction point x3 of the universal joint 30 on the traveling machine body 1 side, so that the end portion is refracted. It moves on the rocking locus a close to the arc around the point x3.
The entire mower 4 moves up and down substantially in parallel with the raising and lowering operation by the link mechanism 18, but the rear end on the upper surface side of the second cover portion 52 attached to the mower 4 side is As the link mechanism 18 moves up and down, it moves on a swing locus b shown in the figure along an arc locus centering on the swing fulcrum of the link portion of the link mechanism 18.

Therefore, in the state where the mower 4 is located at the lower limit, the positional relationship between the first cover portion 51 and the second cover portion 52 is virtually in the vicinity of the illustrated virtual lower limit line d (the axial center position of the transmission shaft 3 at the lower limit). In the state illustrated by the lines, the end portions overlap each other, and the mower 4 is located at the upper limit, the positional relationship between the first cover portion 51 and the second cover portion 52 is the virtual upper limit line u (the upper limit at the upper limit). It is in the state illustrated by the phantom line in the vicinity of the axial center position of the transmission shaft 3, and the ends overlap each other. The imaginary upper limit line u has a forward rising slope with the front side facing upward slightly when the traveling machine body 1 is in the horizontal posture.
When the height of the mower 4 changes from the state in which the mower 4 is positioned in the state of the virtual lower limit line d as described above to the state in which the mower 4 is positioned in the state of the virtual upper limit line u, as shown in FIGS. The length of the transmission shaft 3 is shorter in the latter case than in the former case, and as a result, the overlap margin between the first cover portion 51 and the second cover portion 52 is also determined by the two swing trajectories a and b. Is increased by an amount corresponding to the amount of change.

[Description of Comparative Example]
FIG. 7 shows a comparative example for the present invention. For the sake of convenience, in order to facilitate comparison with the structure of the present invention, the shaft portion of the transmission shaft 3 is added to the structure of the present invention shown in FIG. A structure in which the cover is covered with a cylindrical cover 51 similar to that of the present invention and the periphery of the universal joint 30 on the mower 4 side is covered with a cover 54 is additionally shown.
The cover 54 is not only for allowing the universal joint 30 to bend, but also for allowing the expansion / contraction operation of the transmission shaft 3 caused by the lifting / lowering operation of the mower 4 to be performed. It is necessary to form the direction length longer than the cover part 51b which covers the universal joint 30 part by the side of the traveling body 1 side. The long cover 54 is long in order to prevent the middle portion in the longitudinal direction from being concavely bent and easily brought into contact with the universal joint 30 with the bending operation of the universal joint 30 on the mower 4 side. A shape having a larger diameter is employed in the middle portion in the length direction.
Therefore, the cover 54 itself has a relatively large diameter and length. When the cover 54 configured in this way is used, the height h1 shown in the figure is substantially higher than the position of the belt cover 46 shown in the figure so that the lower part thereof does not interfere with the belt 45 inside the belt cover 46. It is necessary to move upward by a certain degree. In consideration of the height h2 that the upper part of the cover 54 protrudes upward from the second cover 52 shown in the drawing, the height h1 that is shifted upward is added to the height h1 that protrudes upward. About a height (h1 + h2) is required as a space for disposing the cover 46 above the belt cover 46, as compared with the case where the shaft cover 5 of the present invention is provided.

[Other Embodiment 1]
In the best embodiment, the second cover portion 52 of the shaft cover 5 is fixed to the bevel gear case 42, but a second cover portion 52 as shown in FIG. 8 may be adopted. As shown in FIG. 8, the second cover portion 52 is mounted so that one end side thereof is swingable around a fixed fulcrum x4 toward the bell gear case 42 shown in FIG. 4, and the other end side is a free end. It is configured to come into contact with the end portion of the first cover portion 51 by its own weight and to be able to swing up and down according to the angle change of the first cover portion 51 accompanying the raising and lowering of the mower 4.
The free end side is not urged downward by its own weight, but can be urged downward using a helical spring or the like as appropriate, or can be elastically engaged / disengaged with respect to the first cover portion 51. It is also possible to connect them using a simple clamping tool.

[Second embodiment]
The first cover portion 51 of the shaft cover 5 is not limited to the combination of the cylindrical cover portion 51a and the cover portion 51b described in the best embodiment. For example, the first shaft portion 31 and the first cover portion 51 It is composed only of a cylindrical cover portion 51 a that covers the shaft portion of the biaxial portion 32, and is applied to a structural portion that is configured so that the universal joint 30 portion on the traveling aircraft body 1 side enters the counter case 22 of the traveling aircraft body 1. It is good also as composition to do.

[3 of another embodiment]
As the specifications of the mower 4, an appropriate specification such as a configuration configured as a mulching specification, a configuration configured as a side discharge specification, or a configuration configured as a rear discharge specification can be selected. The present invention is also applicable to a front mower in which a mower is supported at the front portion of the traveling machine body 1 so as to be movable up and down.

Overall side view of riding mower Overall plan view of a riding mower Plan view showing the mower part Sectional view in side view showing the transmission structure and shaft cover Sectional view in front view showing the transmission structure and shaft cover Enlarged sectional view in side view showing the transmission structure and shaft cover Sectional view in side view showing a comparative example of the transmission structure and shaft cover Sectional drawing in side view which shows the transmission structure and shaft cover part in other embodiment

Explanation of symbols

1 traveling machine body 3 transmission shaft 4 mower 5 shaft cover 30 universal joint 31 first shaft portion 32 second shaft portion 40 mower deck 51 first cover portion 51a cylindrical cover portion 52 second cover portion

Claims (2)

A riding-type grass mower equipped with a mower suspended from a traveling machine body so as to be able to be raised and lowered and transmitted with a driving force from a traveling machine body via a transmission shaft,
The transmission shaft includes a universal joint connected to each of the output shaft on the traveling machine body and the input shaft on the mower side, and is configured to be refracted at each end, and the outer periphery of the transmission shaft is With a covering shaft cover,
The shaft cover is composed of a combination of a first cover portion mounted on the traveling machine body side and a second cover portion mounted on the mower side,
The first cover portion includes a cylindrical cover portion that covers the shaft portion of the transmission shaft at a position separated from the universal joint portion on the mower side,
The second cover portion covers the mower-side universal joint portion and is configured to cover the mower-side end portion of the first cover portion.   The riding-type mower according to claim 1, wherein the second cover portion is fixedly supported on the mower side.

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