JPH0445378B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transmission device for running a small snow blower, which uses a belt tension clutch and other transmission devices to reduce speed, smooth start-up, and prevent dangerous jumping of the snow blower. The present invention relates to an improvement in deceleration and forward/reverse operation using a friction disk transmission device of a driving friction disk and a driven friction disk. This type of driving power transmission device is used for various small self-propelled machines, such as hand tractor-type lawn mowers, that require low driving power, smooth start-up, and are also desired to be capable of continuously variable speed. It can be used as a driving transmission device.

Conventionally, a power transmission device for running a small snow blower in which a reduction gear is constructed by combining a friction disk transmission device using so-called friction disks and a reduction gear is known (Japanese Utility Model Application Publication No. 126335/1983).

In this mechanism, the movable friction disk is supported by a swing frame or other swing support mechanism that can move toward and away from the fixed friction disk. Since the movable friction disk is supported so that it can be slid in any direction, it is necessary to move one movable friction disk in two different mutually perpendicular directions, which complicates the support mechanism of the movable friction disk and its operation mechanism. There's a problem. In addition, in this mechanism, an initial load is applied by a spring as shown in Fig. 8 so that the movable friction disk supported by the swing frame is always pressed against the fixed friction disk, but when moving backward, the driving torque is As this increases, the running torque reaction force acts against the spring in a direction that moves the movable friction disk away from the fixed friction disk, reducing the pressing force of the movable friction disk against the fixed friction disk and reducing the power transmission ability. do. On the other hand, when moving forward, as the traveling torque increases, the traveling torque reaction force acts in a direction that presses the movable friction disk against the fixed friction disk, and in addition to this, the spring causes the movable friction disk to press against the fixed friction disk. As a result, an excessive pressure contact force is generated on the movable friction disk during forward movement, causing a problem in which the rubber tire is damaged.

In order to solve this problem, it is necessary to have the fixed friction disk and the movable friction disk share the above two moving functions, respectively.

This problem occurs not only when the friction transmission device has two friction discs, but also when one is a conical friction ring and the other is a friction disc, where the driven and driven friction members are at a point on the friction surface. A friction transmission device that performs friction transmission through contact, and shifts one friction disk with respect to the other friction transmission surface with the contact points separated from each other to change speed. This problem is common to those that perform the above-mentioned contact/separation operations and shift operations by moving only the plate.

Furthermore, in the above-mentioned conventional power transmission device for running a small snow blower, the clutch operation system is of a so-called direct coupling type, and the operation force of the operation lever in the clutch engagement direction is directly applied to the friction disks as a force that presses them against each other. transmitted to the disc. Therefore, when the operating lever is roughly operated in the direction of clutch engagement, the operating force acts on the friction surface of the friction disk as an impactful contact force, damaging the friction surface.If this is repeated, the friction surface will It becomes uneven and prevents smooth transmission. Additionally, if the running resistance of the snowplow becomes greater than the transmission force of the friction transmission mechanism, gas slips on the transmission surface and the transmission mechanism is destroyed or damaged due to overload, so the snowplow has a function to prevent this. When the vehicle stops due to high running resistance, the driver often tries to force the operating lever to apply more than a predetermined pressure contact force to the friction surface of the friction disk in order to generate more power than the rated value. Often, when such a large operating force is applied to the friction disk, the drive friction disk itself is destroyed by the large pressing force, making it impossible to operate. In order to prevent the drive friction disk itself from being destroyed, there is no choice but to strengthen the drive friction disk by making it thicker than necessary, but this is extremely wasteful in terms of mechanical design.

The present invention is based on the above-mentioned friction transmission device.
In order to solve the above problem, the contact and separation operations and shift operations of the driven and driven friction disks are divided separately, and the movement of both friction disks is controlled by a single operating lever to ensure safe and smooth operation. The goal is to make it possible to do so.

The measures of the present invention taken to solve this problem are:
It is composed of the following elements.

(a) The shaft of the driven friction disc is rotatably supported by the transmission case, and the driven friction disc is supported by the shaft so as to be shiftable in the axial direction; (b) With respect to the driven friction disc. (c) A driving friction disk is provided so as to be in pressure contact with the driven friction disk, and the driving friction disk is provided so as to be freely shiftable in contact with and away from the driven friction disk by a control mechanism. The disc operating system includes a release mechanism and an operating force transmission mechanism that transmits only the operating force of the operating lever in the clutch release direction to the release mechanism, and the release mechanism connects the driving friction disc to the driven friction disc. The structure shall be configured to release the spring force that presses against the

Incidentally, if the shaft is only rotatable, both of the friction disks will be shifted in the axial direction with respect to the shaft.

Further, as in the prior art, the driven and driven friction discs are operated in conjunction with a single operating lever via operating force transmission means such as rods and links. The "shift" mentioned in (b) above means a shift operation that completely reduces the pressure contact force on the friction transmission surface of the friction disk to zero, and does not necessarily mean a shift operation that is visible to the naked eye. isn't it.

By the way, the driven friction disk shifts only in the axial direction of the shaft whose both ends are rotatably supported, and the driving friction disk is in contact with the driven friction disk.
Shift only in the direction of release. The shifting directions of these two friction disks are at right angles or approximately at right angles to each other. The shift operating means for these two shift operations act on the driven friction disk and the driving friction disk separately, so they do not interfere with each other.
Therefore, the support structure of both friction discs is simple, and the operating mechanism thereof is also simple.

As an embodiment of the present invention, regarding the above means (a), (a) both ends of the shaft are rotatably supported by the side wall of the transmission case, and a driven friction disk is supported on the shaft so as to be slidable in the axial direction. to let

(b) The shaft in (a) above is rotatably and slidably supported in the transmission case, and the driven friction disk is fixed to this shaft.

(c) The axis in (a) above shall be a square axis.

Regarding (b) of the above means, (a) the shaft is rotatably supported by the transmission case, and the driving friction disk, which is provided in pressure contact with the driven friction disk by a spring, is moved by the force of the spring; to be supported by this shaft so as to be able to slide freely in the axial direction against the

(b) A driving friction disk, which is provided so as to be pressed against the driven friction disk by a spring, is fixed to the shaft, and the driving friction disk is brought into contact with and separated from the driven friction disk against the force of the spring. The shaft should be directly or indirectly supported by the transmission case so that the

Regarding (c) above, (a) One end of the biasing spring that biases the drive friction disc in the clutch engagement direction is supported by a release mechanism, that is, a release mechanism such as a release bar, and the release bar is attached to the drive friction disc. The spring force is transmitted to the clutch bar for operating the drive friction disk via the release bar, and the release bar is pushed in the clutch release direction by a member in contact with the clutch bar. In some cases, the transmission of the spring force to the clutch bar is cut off.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a power transmission device for a snow blower according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a schematic structure of a power transmission device for a snow blower. An engine 12 is mounted on a transmission case (also used as a vehicle frame) 10, and the rotational force from this engine 12 is transmitted to a drive shaft 14. . The drive shaft 14 has a running pulley 16 and a snow removal pulley 1.
8 is provided. Pulley 18 is belt 20
The shaft 24 is rotated via the lower pulley 22.
An auger 28 is connected to the tip of the shaft 24 via a worm gear 26, and a blower 30 is further provided on the shaft 24 behind the auger 28. Blower 30
The snow thrown by the auger 28 is thrown toward the chute 32 above.

On the other hand, the traveling pulley 16 rotates the lower pulley 36 via the belt 34. As shown in FIG. 2, a tension roller 38 is pressed against the belt 34 for use as an auxiliary safety clutch. The tension roller 38 is pivotally supported by a support plate 40, and the support plate 40 can swing around a pin 42. A spring 44 is provided at the end 41 of the support plate 40, and the biasing force of the spring 44 causes the second
The roller 38 is positioned at the position indicated by the two-dot chain line in the figure, and the connection between the pulley 16 and the pulley 36 is severed. The support plate 40 is also linked to a gripping lever 50 located near a grip 48 provided at the rear end of the handle lever 46. That is, the grip lever 50 is held in place by the grip 48.
When gripped together, the support plate 40 moves against the biasing force of the spring 44 to the position shown by the solid line in FIG. 2, and the roller 38 presses the belt 34 to connect the pulleys 16 and 36.

The pulley 36 is mounted on a shaft 52, and a driving friction disc 54 is mounted on the opposite end of the shaft 52 from the pulley 36.
4 transmits rotational force by being in pressure contact with the driven friction disk 56, and by shifting the pressure contact position of the driven friction disk 56 with respect to the driving friction disk 54 by the shift fork 128, the shift fork, forward rotation, A reverse switch is made. Prior to this shift operation, the clutch plate 7 whose lower end is supported by a shaft 80 whose both ends are supported by the side walls 10', 10'' of the transmission case 10
6, the driving friction disk 54 is shifted away from the driven friction disk 56 to cut off power transmission and to lighten the shifting operation of the driven friction disk 56.

A small gear 58 is provided on the shaft 138 of the driven friction disk 56, which is rotatably supported on the side walls 10', 10'' of the transmission case ₁₀ via bearings b1, _b2 . An intermediate small gear 61, which is in mesh with the intermediate large gear 60 and is provided on the shaft 60a of the intermediate large gear, is in mesh with a final gear 62.A rotating shaft 64 of the final gear 62 drives a traveling drive wheel (not shown). The driving wheel is the first
The snow blower is driven by driving the crawler 65 shown in the figure.

Next, the transmission comprising the driving friction disk 54 and the driven friction disk 56 will be explained in detail with reference to FIGS. 3 to 5. 3 is a front sectional view of the transmission mechanism, FIG. 4 is a sectional view taken along the line - in FIG. 3, and FIG. 5 is a sectional view taken along the line - in FIG. 4. The friction disk 54 is provided with a boss 66 on its back surface, and this boss 66 has bearings b ₃ ,
The right end 68 in FIG. 4 of the shaft 52, which is rotatably supported on the partition wall 10'' of the transmission case 10 by b ₄ , is inserted.The right end 68 of the shaft 52 has a hexagonal shape, and is The disc 54 receives rotational force from the shaft 52 and can move in the axial direction of the shaft 52.A bearing housing 70 is provided outside the boss 66 of the friction disc 54, and the boss 66 is connected to the bearing housing. It is pivotally supported by a bearing housing 70 via a bearing 72 disposed within the bearing housing 70.A pin 74 is provided protruding from the side on both sides of the bearing housing 70, and this pin 74 is attached to a U-shaped clutch plate 76. Therefore, when the clutch plate 76 swings about the shaft 80 supported by the side walls 10', 10'' of the transmission case 10 to the position shown by the two-dot chain line in FIG. 66 moves to the right together with the bearing housing 70, and the friction disc 54 moves to the right with the bearing housing 70.
It moves to the position shown by the two-dot chain line in the figure and presses the outer peripheral surface of the driven friction disk 56 to transmit rotational force to the driven friction disk 56. The surface of the friction disk 54 is plated with nickel, and the outer periphery of the friction disk 56 is provided with rubber 57. Fibers 57a are embedded in this rubber 57 in the width direction of the friction disk 56.

As shown in FIG. 4, one bent portion 83 of a support plate 82 is fixed to the inside of the transmission case (also used as a vehicle body frame) with a bolt 84, and a hole is formed in the other bent portion 86 of the support plate 82. A clutch bar 90 is movably inserted through 88. The left end 91 of the clutch bar 90 in FIG.
It is locked to. Bent portion 86 and clutch bar 9
A spring 96 is provided between the spring receiver 94 of 0,
The clutch bar 90 is biased to the left in FIG. 4 by this spring 96.

As shown in FIG. 4, a shift bar 9 is installed on the end wall of the transmission case (also used as the vehicle body frame) 10 and the partition wall 10''.
8 is pivotally supported, and a cylindrical body 10 is mounted on this shift bar 98.
0 is attached so as to be slidable in the axial direction. The cylinder 100 is urged rightward in FIG. 4 by a spring 99. The small diameter portion 101 of the cylindrical body 100 is inserted into the notch 103 of the release bar 102, and the release bar 102 is supported by the cylindrical body 100. Further, an end portion 104 of the release bar 102 is engaged with a hole 106 in a support plate 105 attached to a transmission case (also used as a vehicle frame) 10 shown in FIG. Also, the hole 10 at the other end 107 of the release bar 102
8, the end of a clutch bar 90 is movably inserted therethrough. The other end 107 of this release bar 102
A spring 109 is provided between the bent portion 86 of the support plate 82 and
is provided, and the release bar 102 is biased toward the cylindrical body 100 by the spring 109 .
Further, a pin 110 is installed at the right end of the clutch bar 90. When the cylinder 100 moves to the right in FIG. 4, the release bar 102 moves to the right in FIG. 4 due to the urging force of the spring 109, and the pin 1
10 and moves the clutch bar 90 to the right in FIG.

The movement of the cylindrical body 100 is performed by a cam 116 attached to the transmission case (also used as the vehicle body frame) via a bracket 114. That is, the cam 116 is pivotally supported on the bracket 114 by a pin 118,
One end 120 of the cam 116 abuts an end 122 of the cylindrical body 100, and the other end of the cam 116 is connected to a clutch rod 126 via a pin 124. Therefore, when the clutch rod 126 is moved from the position shown by the solid line in FIG. 3 to the position shown by the two-dot chain line, the cam 116 is moved to the position shown by the two-dot chain line in FIG. The clutch plate 76 is moved to the right in FIG. 4 to the position shown by the two-dot chain line in FIG. 3, and the friction disks 54 and 56 are brought into contact with each other. In addition, Clutch Rod 126
The end 127 of the end 127 is pivoted on the pin 124.
It can rotate around the axis of 7.

On the other hand, a fork 12 is attached to a shift bar 98 that is rotatably supported by the end wall of the transmission case and the partition wall 10''.
One end 129 of 8 is fixed. fork 12
A pin 132 protruding from both side surfaces of the bearing housing 131 is pivotally supported at the other end 130 of the bearing housing 131 .
This bearing housing 131 pivotally supports a boss 136 that is integral with the friction disk 56 via a bearing 134 . The boss 136 has bearings b ₁ , b ₂ on the side walls 10', 10'' of the transmission case (also used as the vehicle body frame).
The cross section is supported by a hexagonal shaft 138 so as to be slidable in the axial direction. Therefore, when the driving friction disk 54 is pressed against the driven friction disk 56, the rotational force of the driving friction disk 54 is transmitted to the shaft 138. When the shift lever 98 rotates, the friction disk 56 moves in the axial direction of the shaft 138, and the speed ratio between the friction disk 56 and the friction disk 54 changes.

On the other hand, a shift plate 139 is fixed to the cylindrical body 100 as shown in FIG. 3, and this shift plate 139 has a U-shaped cross section and holds the fork 128 from both sides. Therefore, when the fork 128 swings together with the shift bar 98, the shift plate 139 also swings together. A pin 140 is attached to the end of the shift plate 139.
A guide block 142 is provided in the transmission case (also used as the vehicle body frame) in opposition to the shift plate 139. As shown in FIG. 6, a guide hole 146 is formed in the guide block 142 to maintain a predetermined speed ratio. cam 1
When the pin 16 moves to the position indicated by the two-dot chain line in FIG. 3, the pin 140 moves together with the cylinder 100 and fits into the selected predetermined guide hole 146. The guide hole 146 is selected from the change rod 1 attached to the right end of the shift bar 98 via a universal joint 147.
48 will be operated.

Although not shown, the change rod 148 is connected to the clutch rod 126, and both are connected to a speed change/clutch lever 149 shown in FIG. This transmission/clutch lever 149 is attached to the handle grip 4.
8 is guided by a guide groove 152 of an operation panel 150 (shown in FIG. 7).

The operation of the embodiment according to the present invention constructed as described above is as follows.

Normally, the speed change/clutch lever 149 is located in one of the plurality of recesses 153 of the operation plate 150, and the friction disc 54 is pressed against the friction disc 56 by the spring force of the spring 109, so that the friction The transmission device is in transmission state. From this state, pull the gear shift/clutch lever 149 and press the groove 150 on the operation plate 150.
When the clutch rod 126 is moved to the solid line position, the cam 116 is rotated counterclockwise about the pin 118, and the tip 120 of the cam 116 pushes the cylinder 100 to the left. This movement of the cylinder 100 to the left pushes the other end 107 of the release bar 102 to the left while compressing the spring 109. With this, release bar 1
Since the other end 107 of 02 is separated from the pin 110 at the right end of the clutch bar 90, the transmission of the spring force of the spring 109 to the clutch bar 90 is cut off, and the clutch bar 90 becomes free from the spring force of the spring 109. Therefore, the clutch bar 90 is pushed to the left by the spring force of the return spring 96, pulling the friction disk 54 to the left and away from the friction disk 56 via the clutch plate 76. This cuts off transmission. From this state, shift/clutch lever 1
49 is moved left and right along the groove 152 of the operation plate 150, the shift lever 98 is rotated via the change rod 148, swinging the fork 128 and moving the friction disk 56 along the shaft 138. As a result, a speed change operation is performed, and the friction disk 5
When 6 is in the position shown by the two-dot chain line in FIG. 5, the transmission direction is the reverse direction.

Move the gear shift/clutch lever 149 into any recess 15.
3, the clutch rod 126 becomes 2 in Fig. 3.
It moves to the position shown by the dotted chain line, and the cylindrical body 100 moves to the right. As the cylindrical body 100 moves to the right, the other end 107 of the release bar 102
9 to the right, the spring 109 pushes the clutch bar 90 to the right via the other end 107 of the release bar 102 and the pin 110, and the friction disk 54 is pushed again.
is brought into pressure contact with the friction disk 56. At this time, cylinder 1
00 only moves in the direction away from the other end 107 of the release bar 102, and its operation is not transmitted to the release bar 102. Therefore, if the shift/clutch bar 149 is returned to the recess 153 by an impact, or the shift・Clutch lever 14
Even if 9 is forcibly pushed in the same direction, the cylindrical body will only move away from the release bar 102, and the impactful operating force and forceful operating force will cause the release bar 102,
It is not transmitted to the clutch bar 90. Therefore, the friction disk 54 is not brought into contact with the friction disk 56 by impact or forcibly.

Next, when gripping lever 50 is gripped, pulley 1
6 and pulley 36 are connected, the truck 65 rotates, and the snow blower runs.

In the above embodiment, since the surface of the driving friction disk 54 is nickel-plated, the driven friction disk 56
can prevent wear of the rubber attached to the surface. Furthermore, fibers 57a are embedded in the rubber 57 on the surface of the friction disk 56 in the lateral direction to reinforce the rubber 57.

By the way, when the conventional movable friction disk performs the engagement and separation operations of power transmission and also performs deceleration, forward, and reverse shift operations as a transmission, the support mechanism and operation mechanism are complicated. Therefore, adjustment and maintenance of these mechanisms was not easy. In the present invention, in such a friction disk transmission device, the two friction disks, the driving friction disk and the driven friction disk, are respectively assigned to operate and operate.
In other words, the driving friction disk performs contact and separation operations for power transmission, and the driven friction disk performs separate functions as a transmission, such as deceleration, forward, and reverse shift operations. Therefore, they do not interfere with each other, and therefore, the support mechanism for the friction disks can be simplified, and the operating mechanism thereof can also be simplified. Further, in the present invention, the driven friction disk is not supported by the swing frame, but is rotatably supported by the transmission case, which is a fixed frame, so that the problem as in the prior art does not occur, and as shown in FIG. As shown in , the driving friction disk presses the driven friction disk with an appropriate pressure force set by the spring, so when the driven friction disk moves forward or backward, the increase in running torque and the pressure force of the friction disk are It can be set to increase along an ideal straight line, resulting in stable power transmission.

Furthermore, in the present invention, the operating system of the drive friction disk includes a release mechanism, that is, a release mechanism such as a release bar, and an operating force transmission mechanism that transmits only the operating force of the gear shift/clutch lever in the clutch release direction to the release bar. Since the release bar releases the biasing force of the biasing spring that presses the driving friction disc against the driven friction disc, the operating system can be operated smoothly regardless of manufacturing or assembly errors in the operating system. Even if the transmission/clutch lever is pushed in the direction of clutch engagement, the force will not be transmitted to the drive friction disk, so this impact or forceful push will not be transmitted. It is not possible to impactly or forcefully press the driven friction discs together by force. Therefore, it is possible to prevent damage to the friction surface of the drive and drive friction discs due to rough operation, as well as damage accidents to the drive and drive friction discs, and it is possible to perform gear shifting operations safely and smoothly. It is possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the power transmission mechanism of a snow blower to which an embodiment of the present invention is applied, FIG. 2 is a view taken from the top of FIG. FIG. 3 is a front sectional view thereof, FIG. 4 is a sectional view taken along the line ``-'' in FIG. 3, and FIG. 5 is a sectional view taken along the line ``-'' in FIG.
6 is a sectional view taken along the - line in FIG. 4, FIG. 7 is an explanatory diagram of the operation panel, and FIG. 8A
is a diagram showing the relationship between torque and pressure contact force in the conventional technology,
B is a simplified structural diagram showing a structure related to the above diagram and the prior art, and FIG. 9 is a diagram showing the relationship between torque and pressure contact force of the present invention. 10...Transmission case (also serves as vehicle frame), 1
2...Engine, 16...Traveling drive pulley, 3
4... Belt, 36... Driven pulley, 38... Tension roller, 40... Tension arm, 5
0...Gripping lever, 54...Driving friction disk, 56
...Driven friction disc, 76...Clutch plate, 90...
...Clutch bar, 98...Shift bar, 100...
... Cylinder body, 104 ... Release bar, 116 ... Cam, 126 ... Clutch rod, 148 ... Change rod, 149 ... Speed change/clutch lever.

Claims (1)

[Claims] 1. In a driving power transmission device for a small snow blower having a friction disc transmission device and a gear reduction device, the shaft of the driven friction disc of the driven and driving friction discs of the friction disc transmission device is placed in the transmission case. Rotatably supported,
The driven friction disk is supported by the shaft so as to be freely shiftable in the axial direction, and a driving friction disk is provided so as to be pressed against the driven friction disk by a spring. A driving friction disc is provided so as to be shiftable in contact with and away from the driven friction disc, and an operating system of a change rod for operating the driven friction disc and a clutch rod for operating the driving friction disc is connected to form a single operating lever. A release mechanism and an operation force transmission mechanism for transmitting only the operation force of the operation lever in the clutch release direction to the release mechanism are interposed in the operation system of the drive friction disk, and the release mechanism Accordingly, a power transmission device for running a small snow blower is characterized in that it is configured to release the spring force that presses the driving friction disc against the driven friction disc.