JP4388755B2 - Power transmission mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission mechanism in a management machine or the like.
[0002]
[Prior art]
When performing cutting work with a management machine with a hammer cutter, etc., the operator should hold the left and right handles with his hand and shift while following the management machine on foot in accordance with the traveling speed of the management machine. Operate the lever. Then, the changeover, forward movement, and backward movement of the management machine are performed by a shift lever protruding from the mission case. In addition, in the management machine described in Patent Document 1, in the management machine including a traveling transmission that switches between a forward gear and a reverse gear by operation of a shift lever, switching to backward traveling or backward traveling with the work device driven is performed. It is characterized by having a power transmission mechanism that prohibits
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-59408 [0004]
[Problems to be solved by the invention]
However, in order to switch between the forward and backward movements of the management machine, it is necessary to first stop the main clutch lever to stop the progress of the management machine body, and then re-enter the shift lever to the desired reverse position before starting the management machine. For this reason, there has been an inconvenience of selecting the forward gear and the reverse gear by operating the shift lever every time switching is performed. In particular, in the field where the ground surface is uneven and the outer periphery is not maintained, it is necessary to switch forward and backward as appropriate during the cutting operation by switching forward and backward, and the operator switches between forward and backward. Every time, it is necessary to release the hand from the handle to operate the speed change lever, and there is a problem that work efficiency is poor.
[0005]
Further, the management machine proposed in Patent Document 1 can suppress reverse travel while the work machine is driven from the viewpoint of ensuring safety, but switching to the reverse travel is performed by a shift lever. It is necessary to switch between forward and backward depending on the field condition. Therefore, there is a problem that the traveling direction cannot be easily and instantaneously switched.
[0006]
Accordingly, the present invention solves the above-mentioned conventional problems with respect to a power transmission mechanism that can be applied to a management machine or the like, and does not have the trouble of operating a shift lever and can change the traveling direction of the management machine. The object is to provide a transmission mechanism.
[0007]
[Means for Solving the Problems]
[0008]
The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.
[0009]
In the transmission case (3), a slider (42) for switching between forward and backward movement is provided, and a shift fork (34) for operating the slider (42) is fixed to the fork shaft (32), and the fork shaft (32) One end of the projecting portion projects outwardly from the transmission case (3) to form a projecting portion (32a), and a spring (62) is externally fitted to the projecting portion (32a). ) Is fixed to the front end of the transmission case, and a support plate (60) is fixed to the side surface of the transmission case (3). The support plate (60) is pivotally supported by a fulcrum shaft (65). The lever plate (64) is rotatably arranged. The lever plate (64) pivotally supports a fulcrum shaft (65) on one side, and an operating lever (24) of the handle (22) on the other side. One end of the wire (67) connected to the A protrusion is formed to form a contact portion (64a), and the contact portion (64a) is disposed so as to contact the pin (63) of the fork shaft (32), and the operation lever (24) is operated. Thus, the fork shaft (32) is slid through the wire (67) and the slider (42) is slid, and when the operator releases his hand from the operation lever (24), Due to the biasing force of the spring (62), the fork shaft (32) is pushed out to the outside of the transmission case (3) via the pin (63), and the slider (42) is biased in the protruding direction which is the forward direction. It is what is done.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an overall view of the management machine, FIG. 2 is a front sectional view of the mission case, FIG. 3 is a partial front sectional view of the mission case, and FIG. 4 is a partial front sectional view of the mission case. FIG. 5 is a rear view of the fork drive unit, and FIG. 6 is a rear view of the fork drive unit. Furthermore, FIG. 7 is a side view in the transmission case.
[0011]
First, the overall structure of the management machine 1 will be described with reference to FIG. In addition, let the side which provided the working machine in FIG. 1 be the front. In the management machine 1, an engine 2 is disposed at the rear, the engine 2 is fixed on an engine frame 5, and a fuel tank 6 is mounted on the upper part of the engine 2. The transmission case 3 is fixed to the front portion of the engine frame 5. As will be described later, power is transmitted from the output shaft 8 of the engine 2 to the input shaft 7 of the transmission case 3 via an endless belt 13, and the belt 13 and the like are covered with a transmission case 9. An axle 11 is pivotally supported at the lower part of the transmission case 3, and traveling wheels 12 are fixed to the axle 11 so as to be able to travel.
[0012]
A hammer cutter 4 is disposed in front of the mission case 3. A chain case 15 is disposed in the center of the left and right shafts of the hammer cutter 4 so that power can be transmitted and driven by a PTO shaft (not shown) that is provided laterally on the transmission case 14 above the chain case 15. A cutter rotating shaft 16 is horizontally mounted on the lower part of the chain case 15, and the bases of a large number of Y-shaped or T-shaped cutter blades 17, 17... Are pivotally supported on the cutter rotating shaft 16. ing. The upper and lateral sides of the rotation trajectory at the tip of the cutter blades 17, 17... Are covered with a cutter cover 18. An auxiliary wheel 19 is disposed at a lateral position in the vicinity of the cutter rotation shaft.
[0013]
A handle base 21 is provided in the upper part of the transmission case 3, and a handle 22 is disposed on the handle base 21 so as to be able to change back and forth by rotating in the front-rear horizontal direction. The handle 22 is provided with an operation lever 24, a main clutch lever 25, side clutch levers 26 and 26, etc., which are operation means for switching between forward and backward movement. A shift lever 27 protrudes from the right front part of the handle base 21 so as to be able to change back and forth. In order to allow the operator to perform the input operation of the operation lever 24 without releasing his / her hand from the handle 22, the operation lever 24 is disposed in the vicinity of the grip 22a of the handle 22 as shown in FIG. Is preferred.
[0014]
Next, the power transmission mechanism according to the present invention in the management machine 1 having the overall structure as described above will be described. First, the internal configuration of the mission case 3 will be described with reference to FIGS. In the mission case 3, the input shaft 7, the PTO shaft 28, the main shaft 29, the transmission shaft 30, the fork shafts 31 and 32, etc. are horizontally mounted in the horizontal axis direction. One end of the input shaft 7 protrudes outward from the mission case 3 and the other end is a PTO shaft 28. A transmission gear 45 is loosely fitted on the input shaft 7, a sprocket 51 is fixed, and a sliding gear 40 is spline-fitted so as to be slidable in the axial direction. The transmission gear 45 is formed with external teeth 45 a and 45 b, and the external teeth 45 b are always meshed with external teeth 46 a of a large-diameter gear 46 fixed on the transmission shaft 30. A shift fork 33 is fitted to the sliding gear 40, and the shift fork 33 is fixed to the fork shaft 31. The fork shaft 31 is connected and interlocked with the speed change lever 27, and the sliding gear 40 is formed with external teeth 40a for low speed travel and external teeth 40b for high speed travel.
[0015]
Gear portions 44 are formed at left and right ends on the main shaft 29, and the gear portions 44 are always meshed with external teeth 46a formed on the transmission gear 45. Further, a forward / reverse switching mechanism is provided on the main shaft 29, and the reverse sprocket 53 and the forward gear 41 are loosely fitted on the left and right central portions of the main shaft 29, and the slider 42 slides between them. Spline fitting is possible. A chain 52 is wound between the reverse sprocket 53 and the sprocket 51 to constantly transmit power. The forward gear 41 is formed with one internal tooth 41c and two external teeth 41a / external teeth 41b. When the sliding gear 40 slides, the external gear 41a and the sliding gear 40 are for low-speed traveling. The external teeth 40a or the external teeth 41b and the high-speed traveling external teeth 40b can be engaged with each other.
[0016]
The slider 42 is formed with external teeth 42a and side teeth 42b. By sliding of the slide gear, the external teeth 42a are formed on the internal teeth 41c of the forward gear 41, and the side teeth 42b are formed on the side surfaces of the reverse sprocket 53. It is possible to mesh with the formed side teeth 53a. Further, a shift fork 34 is fitted to the slider 42, and the shift fork 34 is fixed to the fork shaft 32. The fork shaft 32 is connected to the operation lever 24 via a wire or the like. As will be described later, the slider 42 is slid to the forward gear 41 side (right side in FIG. 2) in the normal state, and the external teeth 42a are engaged with the internal teeth 41c of the forward gear 41. A large-diameter gear 30 and an output sprocket 47 are fixed to the transmission shaft 30. The power transmitted to the output sprocket 47 is transmitted to a sprocket 49 fixed to the axle 11 via a chain 50.
[0017]
The flow in which the power input to the input shaft 7 is transmitted to the axle 11 in the above configuration will be described. First, when the management machine 1 having the power transmission mechanism according to the present invention moves forward at low speed, the sliding gear 40 is slid leftward, and the sliding gear 40 moves forward with the low-speed traveling external teeth 40a. The external teeth 41a of the gear 41 are engaged with each other. Further, when moving forward at a high speed, the sliding gear 40 is slid rightward, and the high-speed traveling external teeth 40 b of the sliding gear 40 and the external teeth 41 b of the forward gear 41 are engaged. Then, the slider 42 is slid to the right, and the outer teeth 42 a are engaged with the inner teeth 41 c of the forward gear 41. Thus, during forward movement, the input shaft 7 → sliding gear 40 → forward gear 41 → slider 42 → main shaft 29 → gear portion 44 → transmission gear 45 → large diameter gear 46 → transmission shaft 30 → output sprocket 47 → chain 50 → Sprocket 49 → Axle 11 and power are transmitted.
[0018]
On the other hand, in order to move the management machine 1 backward, the slider 42 is slid leftward when the operation lever 24 is operated, and the side teeth 42b of the slider 42 are formed on the reverse sprocket 53. It meshes with the side teeth 53a. Accordingly, at the time of reverse movement, the input shaft 7 → sprocket 51 → chain 52 → reverse sprocket 53 → slider 42 → main shaft 29 → gear portion 44 → transmission gear 45 → large diameter gear 46 → transmission shaft 30 → output sprocket 47 → chain Power is transmitted to 50 → sprocket 49 → axle 11.
[0019]
Next, an operation mechanism of the fork shaft 32 by operating the operation lever 24 will be described. A mechanism for urging the forward / reverse switching mechanism toward the forward side is provided on the side of the transmission case 3, and as shown in FIGS. 5 and 6, the right end of the fork shaft 32 is The protrusion 32a is formed to protrude outward from the mission case 3. A spring 62 and a retaining ring 61 are externally fitted to the projecting portion 32a, and a pin 63 is fixed to the distal end portion to prevent it from coming off, and the fork shaft 32 is urged by the spring 62 in the projecting direction. Further, a support plate 60 is fixed to the side surface of the transmission case 3 through the projecting portion 32a or pivotally supported by the fork shaft 32. The support plate 60 is formed in a U-shape when viewed from the front, It passes through the fork shaft 32. A lever plate 64 pivotally supported by a fulcrum shaft 65 is rotatably disposed at the lower outer end of the support plate 60. The lever plate 64 has a convex shape when viewed from the side, and pivotally supports the fulcrum shaft 65 on the lower side, locks one end of the wire 67 on the lower side with a pin 66, and forms a protrusion on the upper center. A contact portion 64a is formed. Further, the corresponding contact portion 64 a is disposed so as to always contact the pin 63. The wire 67 is guided through the upper part of the support plate 60 at the midway portion, and the other end is connected to the operation lever 24. Then, the fork shaft 32 is slid by the operation of the operation lever 24, and the slider 42 is also interlocked with the sliding.
[0020]
That is, as shown in FIGS. 3 and 5, in a state where the operator releases his hand from the operation lever 24, that is, in a state where the input operation of the operation lever 24 is not performed, the urging force of the spring 62 causes the The fork shaft 32 is pushed out to the outside of the transmission case 3 via the pin 63, and is held so that the protruding length of the protruding portion 32a is L1. The slider 42 is slid rightward by the shift fork 34 fixed to the fork shaft 32, and the outer teeth 42 a of the slider 42 are engaged with the inner teeth 41 c of the forward gear 41. Accordingly, when the operation lever 24 is not operated, the management machine 1 travels forward.
[0021]
On the other hand, as shown in FIGS. 4 and 6, when the operator rotates the operation lever 24 backward, the lever plate 64 is forcibly rotated upward via the wire 67. . Then, the abutting portion 64a abuts against the pin 63 and pushes in, the fork shaft 32 is pushed inward of the transmission case 3, and the projecting length of the projecting portion 32a is held at L2. Therefore, when the input operation is performed, the slider 42 is instantaneously slid leftward by the shift fork 34, and the side teeth 42b of the slider 42 are engaged with the side teeth 53a formed on the retreating sprocket 53. Without operating the speed change lever 27, the traveling of the management machine 1 can be instantaneously switched from forward to backward.
[0022]
Further, when the operator releases the operation lever 24 from the state where the input operation is performed, the fork shaft 32 is pushed out to the outside of the transmission case 3 by the urging force of the spring 62, and the protrusion 32 a The projecting length is returned to L1. Then, since the slider 42 is engaged with the forward gear 41 from the reverse sprocket 53, the traveling of the management machine 1 can be instantaneously returned from backward to forward.
[0023]
Therefore, according to this power transmission mechanism, there is no trouble of operating the shift lever 27 to select the forward speed and the reverse speed each time the forward / backward movement of the management machine 1 is switched, and the hand 22 is released from the handle 22. The operator can switch back and forth without moving. Further, according to the cutting work, the management machine 1 can be moved forward / backward as appropriate, and when it hits a wall or the like, it can be moved backward to change the traveling direction, thereby improving the efficiency of the cutting work. is there.
[0024]
In particular, when working with frequent switching between forward and reverse, such as cutting with the hammer cutter 4, it is not necessary to operate the main clutch lever to operate the main shift lever and switch between forward and reverse. The lever 24 can be switched to reverse only by rotating backward, and can be switched to forward only by releasing the hand from the operation lever 24, so that the operability can be improved.
[0025]
Similar to the power transmission mechanism according to the present embodiment, the same effect can be obtained not only by arranging the hammer cutter 4 behind the management machine 1 but also by arranging a work device such as a rotary tiller. it can. Further, the present invention can be applied not only to a management machine in which a work device is disposed behind the mission case 3, but also to a two-wheeled small management machine that performs plowing and traveling at the same time. The two-wheeled small management machine is particularly effective in that the power mechanism of the management machine can be simplified and the operability of the management machine body can be improved.
[0026]
Further, in the input operation of the operation lever 24, unlike the present embodiment, the power transmission mechanism is such that the management machine 1 is moved forward when the input operation is being performed and is retreated when the input operation is not performed. The same effect can be achieved.
[0027]
Next, an embodiment of the main clutch of the power transmission mechanism according to the present invention will be described. 2. Description of the Related Art Conventionally, in a power transmission mechanism that transmits driving from an engine by a tension pulley type clutch mechanism, the tension of the engine is adjusted by bringing a single tension roller disposed in the main clutch into contact with the belt to adjust the belt tension. The drive is transmitted and disconnected from Therefore, the conventional clutch mechanism in which one tension roller is brought into contact with the belt has a problem that the belt has a large refraction angle and short durability. In addition, since a load is applied to one tension roller, there is a problem that the life of the bearing is shortened.
[0028]
Therefore, in this embodiment, as shown in FIG. 7, the duplex tension rollers 82 and 82 are brought into contact with the belt 13. That is, a plurality of tension rollers 82 and 82 constituting a belt tension type clutch are supported on a support plate 85 serving as a support body so as to be rotatable along the belt 13, and the central portion of the support plate 85 is pivoted to a tension arm 83. In support of this, a plurality of tension rollers 82 and 82 are disposed so as to be able to contact the belt 13 simultaneously. Specifically, an input pulley 81 and an output pulley 80 are fixed to the input shaft 7 of the mission case 3 and the output shaft 8 of the engine 2, respectively, and power is transmitted via the belt 13. A tension pulley type main clutch 10 is disposed between the output shaft and the input shaft. The main clutch 10 includes a plurality of (two in this embodiment) tension rollers 82 and 82 rotatably supported by a support plate 85, and a tension for pivotally supporting the support plate 85 by a fulcrum shaft 84. The fulcrum shaft 84 is provided at the center between the tension rollers 82 and 82, and the fulcrum shaft 84 is pivotally supported at the tip of the tension arm 83. The main clutch lever 25 is connected to the tension arm 83 via a main clutch lever 25 disposed on the handle 22 and a wire (not shown), and is operated by the main clutch lever 25.
[0029]
When the main clutch lever 25 is operated in the entering direction, the tension arm 83 is rotated in a direction in which the tension rollers 82 and 82 abut against the belt 13 to be tensioned. When the tension arm 83 is rotated, the tension rollers 82 and 82 are rotated about the fulcrum shaft 84 so as to be biased with substantially the same pressure. When each tension roller 82 comes into contact with the belt 13 and is tensioned, the tension roller 82 or 82 obtains tension on the belt 13, and the drive from the engine 2 is driven by the output shaft 8 → output pulley 80 → belt 13 → input. It is transmitted from the pulley 81 to the input shaft 7. On the other hand, when the main clutch lever 25 is operated in the turning direction, the tension arm 83 is rotated in a direction for separating the tension rollers 82 and 82 from the belt 13. Accordingly, the belt 13 is not tensioned, and the drive from the engine 2 is not transmitted to the input shaft 7.
[0030]
In such a power transmission mechanism, when the main clutch lever 25 is operated in the entering direction, the two tension rollers 82 and 82 are brought into contact with the belt 13, so that the refraction angle of the belt 13 is one. This is more relaxed than when the tension roller is in contact. Therefore, the durability time of the belt 13 can be extended. Further, since the load per one of the tension rollers 82 in contact with the belt 13 is reduced, the life of the bearing portion of the tension roller 82 can be extended. Further, since the duplex tension rollers 82 and 82 are brought into contact with the belt 13, the stroke when the tension of the belt 13 is turned on or off can be shortened.
[0031]
The tension roller is not limited to a double type, and the same effect can be obtained as long as two or more tension rollers are arranged in series and brought into contact with the belt 13.
[0032]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0033]
In the transmission case (3), a slider (42) for switching between forward and backward movement is provided, and a shift fork (34) for operating the slider (42) is fixed to the fork shaft (32), and the fork shaft (32) One end of the projecting portion projects outwardly from the transmission case (3) to form a projecting portion (32a), and a spring (62) is externally fitted to the projecting portion (32a). ) Is fixed to the front end of the transmission case, and a support plate (60) is fixed to the side surface of the transmission case (3). The support plate (60) is pivotally supported by a fulcrum shaft (65). The lever plate (64) is rotatably arranged. The lever plate (64) pivotally supports a fulcrum shaft (65) on one side, and an operating lever (24) of the handle (22) on the other side. One end of the wire (67) connected to the A protrusion is formed to form a contact portion (64a), and the contact portion (64a) is disposed so as to contact the pin (63) of the fork shaft (32), and the operation lever (24) is operated. Thus, the fork shaft (32) is slid through the wire (67) and the slider (42) is slid, and when the operator releases his hand from the operation lever (24), Due to the biasing force of the spring (62), the fork shaft (32) is pushed out to the outside of the transmission case (3) via the pin (63), and the slider (42) is biased in the protruding direction which is the forward direction. since the, for example, when applied to the management machine without the inconvenience of selecting a the forward gears and the reverse gear by operating the shift lever, the operator can advance and return before releasing the handle. Furthermore, when it hits against a wall or the like, it can be retracted instantaneously and the direction of travel can be switched to improve work efficiency.
[Brief description of the drawings]
FIG. 1 is an overall view of a management machine.
FIG. 2 is a front sectional view of a mission case.
FIG. 3 is a partial front sectional view of a mission case.
FIG. 4 is a partial front sectional view of the same mission case.
FIG. 5 is a rear view of the fork drive unit.
FIG. 6 is a rear view of the fork drive unit.
FIG. 7 is a side view inside the transmission case.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control machine 3 Mission case 7 Input shaft 24 Operation lever 29 Main shaft 30 Transmission shaft 34 Shift fork 41 Forward gear 42 Slider 53 Backward sprocket

Claims (1)

In the transmission case (3), a slider (42) for switching between forward and backward movement is provided, and a shift fork (34) for operating the slider (42) is fixed to the fork shaft (32), and the fork shaft (32) One end of the projecting portion projects outwardly from the transmission case (3) to form a projecting portion (32a), and a spring (62) is externally fitted to the projecting portion (32a). ) Is fixed to the front end of the transmission case, and a support plate (60) is fixed to the side surface of the transmission case (3). The support plate (60) is pivotally supported by a fulcrum shaft (65). The lever plate (64) is rotatably arranged. The lever plate (64) pivotally supports a fulcrum shaft (65) on one side, and an operating lever (24) of the handle (22) on the other side. Lock one end of the wire (67) connected to the upper center A protrusion is formed to form a contact portion (64a), and the contact portion (64a) is disposed so as to contact the pin (63) of the fork shaft (32), and the operation lever (24) is operated. Thus, the fork shaft (32) is slid through the wire (67) and the slider (42) is slid, and when the operator releases his hand from the operation lever (24), Due to the biasing force of the spring (62), the fork shaft (32) is pushed out to the outside of the transmission case (3) via the pin (63), and the slider (42) is biased in the protruding direction which is the forward direction. a power transmission mechanism, characterized in that it is.

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