JP7707046B2 - Work equipment - Google Patents

Description

The present invention relates to a work machine, and in particular to a walk-behind work machine that includes a handle provided at the rear of the machine body.

Conventionally, a known working machine includes a body, left and right running units each including a drive wheel and a driven wheel, a working unit for performing a specified task, a drive source for driving the working unit and the running unit, and a height change mechanism for changing the height of the working unit relative to the running unit. For example, Patent Document 1 discloses a snowplow with such a configuration. In this snowplow, the working unit frame is supported rotatably relative to the running unit frame around the axle of the drive wheel via a height change mechanism having one end connected to the running unit frame that supports the running unit and the other end connected to the working unit frame that supports the working unit.

This height change mechanism includes a first bracket that is supported on one of the traveling unit frame and the working unit frame and includes a rack that extends vertically; a second bracket that is supported on the other of the traveling unit frame and the working unit frame; an electric motor supported on the second bracket; a worm attached to the output shaft of the electric motor; a worm wheel that meshes with the worm; and a pinion that is provided on the worm wheel and meshes with the rack. When the electric motor rotates, the worm, worm wheel, and pinion rotate in conjunction with each other, and the rack (first bracket) moves up and down relative to the second bracket due to the rotation of the pinion. This causes the working unit to swing relative to the traveling unit around the axle of the drive wheel as the center of rotation, changing the height of the working unit relative to the traveling unit.

JP 2017-115305 A

However, in the work machine (snow removal machine) described in Patent Document 1, the working unit frame rotates relative to the running unit frame due to the vertical movement of the rack, so when changing the height of the working unit by a relatively large amount, a rack with sufficient height is required. This poses the problem that it is difficult to make the height changing mechanism compact.

In view of the above background, the present invention aims to provide a work machine with a compact configuration in which the working unit can be rotated relative to the running unit.

In order to solve the above problem, one aspect of the present invention is a working machine (1) comprising a running frame (3a) supporting left and right running parts including drive wheels (15) and driven wheels (16), respectively; a work frame (3b) that is rotatably mounted on the running frame around the axle (19) of the drive wheels as a rotation center and supports a working part (6, 7) for performing a predetermined task; a drive source (10) for driving the working part and the running part; and a rotating device interposed between the running frame and the work frame for rotating the work frame around the rotation center relative to the running frame. and a rotating device (8), the rotating device including an equipment frame (44), an electric motor (45) fixed to the equipment frame, a worm (54) attached to the output shaft (50) of the electric motor, a worm wheel (55) rotatably supported on the equipment frame and meshing with the worm, a transmission shaft (62) rotatably supported on the equipment frame and extending in the left-right direction, driven by the worm wheel, and a link mechanism (64) provided between the traveling frame and the working frame and driven by the transmission shaft.

According to this aspect, the link mechanism can be driven by the rotation of the electric motor, so that the working part can be rotated relative to the running part with the axle of the drive wheel as the center of rotation, making it possible to change the height of the working part relative to the running part with a compact configuration.

In the above embodiment, the worm and the transmission shaft may be perpendicular to each other.

In this embodiment, the worm and the transmission shaft of the second gear are arranged perpendicular to each other, making it possible to reduce the size of the rotating device.

In the above embodiment, the transmission shaft is integral with a second gear (61) connected to the worm wheel via a reduction mechanism (59), the reduction mechanism includes a small gear (58) integral with the worm wheel, and the transmission shaft of the second gear is parallel to the rotation axis (56) of the worm wheel.

According to this aspect, an even greater reduction ratio can be obtained between the output shaft and the transmission shaft, making it possible to increase the rotational speed of the electric motor, and thus outputting a relatively large torque even if the electric motor is relatively small.

In the above embodiment, the second gear may be a sector gear having a fan shape.

This allows the rotation device to be made smaller.

In the embodiment in which the second gear is the sector gear, the device frame defines a gear chamber (46) that houses a gear train that connects the electric motor to the link mechanism, and the second gear is rotatably provided between a first position where it abuts against a first portion (68) of the device frame in one direction of rotation and a second position where it abuts against a second portion (69) of the device frame in the other direction of rotation.

According to this aspect, by controlling the output of the electric motor when the second gear hits the first or second part, the braking function of the electric motor can be omitted, making it possible to further miniaturize the rotating device.

In the above embodiment, the device frame may be formed with a breather opening (74, 77) that connects the gear chamber to the outside.

According to this aspect, the air in the gear chamber can be released to the outside through the breather opening, preventing fluctuations in pressure in the gear chamber due to temperature changes.

In the above embodiment, the traveling frame may include left and right side members (37) extending in the front-rear direction, a rear member (38) extending in the left-right direction and connecting the rear portions of the side members to each other, and a substantially L-shaped support bracket (39) connected to the rear and upper surfaces of the rear member, and the link mechanism may include a drive arm (65) connected to the transmission shaft, and a drive link (66) having a free end of the drive arm and an end pivoted to the support bracket.

In this embodiment, one end of the link mechanism is connected to the running frame via a support bracket, which increases the rigidity of the link mechanism against forward stress.

It is possible to provide a compactly configured work machine in which the working part can be rotated relative to the running part.

FIG. 1 is a side view of a snow blower according to an embodiment of the present invention. FIG. 1 is a perspective view of a snow blower according to an embodiment of the present invention, seen from the left rear; FIG. 1 is a perspective view of a rotation device according to an embodiment of the present invention; FIG. 4 is a cross-sectional view of the rotation device according to the present embodiment taken along line IV-IV in FIG. 3 as viewed from the front. FIG. 4 is a cross-sectional view of the rotation device according to the present embodiment taken along line V-V in FIG. 3 from the left. FIG. 6 is a cross-sectional view of the rotating device according to the present embodiment taken along line VI-VI in FIG. 3 from the left. FIG. 1 is a side view showing a snow blower according to an embodiment of the present invention when a second gear is in a first position; FIG. 1 is a side view showing the snow blower when the second gear is in a second position according to the embodiment; 1 is a time chart showing the relationship between the rotation angle of the second gear, the electric current of the electric motor, and the torque of the electric motor according to the present embodiment;

Embodiments of the present invention will be described in detail below with reference to the drawings. In the following embodiments, the present invention is applied to a snowplow 1. In the following, terms indicating directions such as front/rear, left/right, up/down, etc. are used based on the directions as seen by the operator operating the snowplow 1. In the drawings, the arrow indicated with "Fr" points forward.

Figure 1 is a side view of a snow blower 1 according to this embodiment. First, the overall configuration of the snow blower 1 will be described with reference to Figure 1.

As shown in FIG. 1, the snowplow 1 is a walk-behind snowplow in which an operator walks behind to remove snow. The snowplow 1 has a body 3 that forms the framework of the snowplow, a pair of traveling devices 4 provided on both the left and right sides of the body 3, a handle device 5 provided at the rear of the body 3, a blower device 6 provided in front of the body 3, and an auger device 7 provided in front of the blower device 6. In FIG. 1, only the traveling device 4 provided on the left side of the body 3 is shown.

Both traveling devices 4 are supported by a traveling frame 3a (Fig. 2) provided at the bottom of the machine body 3. The blower device 6 and the auger device 7 constitute the working section of the snow removal machine 1 for performing snow removal work. The blower device 6 and the auger device 7 are supported by a work frame 3b (Fig. 2) provided at the front and top of the machine body 3. The traveling frame 3a and the work frame 3b are rotatably connected to each other at the front. The work frame 3b is provided with a rotation device 8 that adjusts the height of the auger device 7 by rotating the work frame 3b relative to the traveling frame 3a. The rotation device 8 will be explained in detail later.

An internal combustion engine (hereinafter referred to as "engine 10") is supported on the upper part of the machine body 3 as a drive source. The engine 10 has a crankshaft 11 (only the front end portion is shown in FIG. 1) that can rotate around an axis that extends in the front-rear direction. Note that in other embodiments, the crankshaft 11 may be rotatable around an axis that extends in the up-down direction.

A transmission shaft 12 that can rotate around an axis that extends in the front-rear direction is provided at the lower front of the machine body 3. The transmission shaft 12 is positioned lower than the crankshaft 11 and is connected to the crankshaft 11 via a reduction mechanism 13. The reduction mechanism 13 has a small diameter drive pulley 13a connected to the crankshaft 11, a large diameter driven pulley 13b connected to the transmission shaft 12, a belt 13c wound around both pulleys, and a tensioner (not shown).

Each traveling device 4 is an endless track having a driving wheel 15, a driven wheel 16 provided behind the driving wheel 15, and a crawler belt 17 wound around the driving wheel 15 and the driven wheel 16. In other embodiments, the driven wheel 16 may be provided in front of the driving wheel 15, and the traveling device 4 does not have to be an endless track. Both traveling devices 4 constitute the traveling part of the snow blower 1 for traveling the machine body 3. The machine body 3 is located between both traveling devices 4. A traveling motor 18 is connected as a driving source to the driving wheel 15 of each traveling device 4 via a drive shaft 19 for transmitting driving force. At least one traveling motor 18 is required, but in this embodiment, two traveling motors 18 arranged on the left and right are provided (only the left traveling motor 18 is shown in FIG. 1).

The handle device 5 has left and right arms 20 (only the left arm 20 is shown in FIG. 1) that extend rearward and upward from the bottom of the machine body 3, and an input device 21 attached to the upper end of the left and right arms 20. A grip 20a that is held by the operator is provided at the upper end of each arm 20. The input device 21 is a device that accepts input operations by the operator. The input device 21 has, for example, a travel lever 22 that accepts travel operations of the snow removal machine 1, a snow removal switch 23 that accepts operation operations of the blower device 6 and the auger device 7, a rotation switch 24 that accepts rotation operations of the rotation device 8 by the operator, and a deadman clutch 25 arranged close to the grip 20a.

The blower device 6 has a blower housing 26 fixed to the front of the aircraft body 3, a blower 27 housed in the blower housing 26, and a chute 28 extending upward from the upper end of the blower housing 26. The blower 27 is fixed to the rear of the transmission shaft 12.

The auger device 7 has an auger housing 31 fixed to the front of the blower housing 26, an auger shaft 33 rotatably supported on the auger housing 31 and connected to the transmission shaft 12 via a transmission 32, and an auger claw 34 fixed to the auger shaft 33.

Next, the overall operation of the snow blower 1 will be explained.

When the operator operates the travel lever 22 of the input device 21 to drive the snow blower 1, the travel motor 18 of each travel device 4 rotates. The rotation of the travel motor 18 is transmitted to the drive wheels 15 via the drive shaft 19. This causes the crawler belt 17 to rotate and the snow blower 1 to travel.

When the operator operates the snow removal switch 23 of the input device 21 to operate the blower device 6 and the auger device 7, the crankshaft 11 of the engine 10 rotates. The rotation of the crankshaft 11 is transmitted to the transmission shaft 12 via the reduction mechanism 13, and the transmission shaft 12 and the blower 27 rotate together. The rotation of the transmission shaft 12 is transmitted to the auger shaft 33 via the transmission 32, and the auger shaft 33 and the auger claws 34 rotate together. When the auger claws 34 rotate, the snow in front of the snow remover 1 is crushed by the auger claws 34 and collected in the left-right center of the auger housing 31. This collected snow is introduced into the blower housing 26 and projected in the desired direction by the blower 27 through the chute 28.

Next, the running device 4 of the snow blower 1 will be described in detail with reference to FIG. 2.

As shown in FIG. 2, the traveling device 4 is supported by a traveling frame 3a provided on the lower part of the machine body 3. In detail, the traveling frame 3a supports left and right traveling parts including the driving wheels 15 and the driven wheels 16. The traveling frame 3a includes left and right side members 37 extending in the front-rear direction and a rear member 38 extending in the left-right direction and connecting the rear parts of the side members 37 to each other. A substantially L-shaped support bracket 39 is connected to the rear and upper surfaces of the rear member 38. In this embodiment, the support bracket 39 is welded to the rear and upper surfaces of the rear member 38. The support bracket 39 has a substantially plate shape with its main surface facing left and right. Two support brackets 39 are arranged at approximately the center of the rear member 38 in the left-right direction, at a predetermined distance apart in the left-right direction.

Next, the rotation device 8 of the snow removal machine 1 will be described in detail with reference to Figures 2 to 5. The rotation device 8 is a device for rotating the work frame 3b relative to the traveling frame 3a around the drive shaft 19 as the center of rotation when changing the height of the auger device 7 relative to the traveling device 4.

The rotation device 8 is interposed between the traveling frame 3a and the working frame 3b. In this embodiment, as shown in FIG. 2, the rotation device 8 is disposed to the left of the machine body 3. In another embodiment, the rotation device 8 may be disposed to the right of the machine body 3, or may be disposed in the center of the machine body 3 in the left-right direction.

As shown in FIG. 3, the rotation device 8 includes a device frame 44, which is a rigid member, and an electric motor 45 fixed to the device frame 44. As shown in FIG. 4, the device frame 44 defines a gear chamber 46 (FIGS. 5 and 6) at its inner lower part that houses a gear train that connects the electric motor 45 to a link mechanism 64 (described later). The device frame 44 also defines a breather chamber 71 at its inner upper part. The breather chamber 71 is located above the gear chamber 46. The gear chamber 46 and the breather chamber 71 are connected to each other via a communication hole 72.

A first breather opening 74 is formed at the top of the breather chamber 71, opening the breather chamber 71 outward to the left and right. One end of a breather tube 75 extending outward to the left and right from the top of the breather chamber 71 is inserted into the first breather opening 74. One end of the breather tube 75 is fixed to the device frame 44 by a tubular first fixing member 76 inserted from the inside of the left and right of the first breather opening 74. In addition, a second breather opening 77 is formed in the device frame 44, connecting the gear chamber 46 to the outside. The other end of the breather tube 75 is fixed to the device frame 44 by a tubular second fixing member 78 inserted from below the second breather opening 77. With these configurations, the gear chamber 46 is connected to the outside of the device frame 44 via the breather tube 75 that connects the first breather opening 74 and the second breather opening 77, making it possible to release the air in the gear chamber 46 to the outside via the second breather opening 77, preventing fluctuations in pressure in the gear chamber 46 due to temperature changes.

As shown in Figures 3 and 4, a cover part 48 is attached to the upper part of the left side wall 44a of the device frame 44. The cover part 48 extends upward and rearward from the upper part of the left side wall 44a of the device frame 44. The cover part 48 is disposed to the left of the device frame 44 and the electric motor 45, and protects the device frame 44, the electric motor 45, and the breather tube 75 from the left.

As shown in FIG. 3, the rear wall 44b of the device frame 44 is provided with two fastening holes (not shown) that penetrate the rear wall 44b from front to rear, spaced a predetermined distance above and below. Between the two fastening holes of the device frame 44, an opening (not shown) is provided that penetrates the rear wall 44b from front to rear. In addition, a tube portion 44d is formed at the bottom of the right side wall 44c (FIG. 4) of the device frame 44, extending inwardly to the left and right from the right side wall 44c.

As shown in FIG. 5, the electric motor 45 includes an output shaft 50 rotatably received in an opening in the rear wall 44b, and an electric motor body 51 having a cylindrical shape centered on the output shaft 50. As shown in FIGS. 2 and 3, the output shaft 50 is inclined upward toward the rear. As shown in FIG. 5, a flange 52 is formed on the front edge of the electric motor body 51, extending radially outward from the front edge. The flange 52 is provided with a fastening hole (not shown) that penetrates the flange 52 from front to rear. The flange 52 is fastened to the rear wall 44b of the device frame 44 by a bolt inserted through the fastening hole of the device frame 44 and the fastening hole of the flange 52, and a nut screwed onto the bolt.

The rotating device 8 further includes a worm 54 attached to the output shaft 50 of the electric motor 45, and a worm wheel 55 rotatably supported on the device frame 44 and meshing with the worm 54. The worm 54 is arranged coaxially with the output shaft 50 at the front end of the output shaft 50. The lead angle of the worm 54 is set to be equal to or less than the friction angle, and a self-locking effect is generated with respect to the worm wheel 55. The worm wheel 55 is arranged below the worm 54 at a position corresponding to the left and right of the worm 54. The rotation axis 56 of the worm wheel 55 extends to the right from the center of the worm wheel 55. The worm 54 (and the output shaft 50 of the electric motor 45) and the rotation axis 56 of the worm wheel 55 are perpendicular to each other.

The worm wheel 55 is provided with a reduction mechanism 59 including a small gear 58 that is integral with the worm wheel 55. The small gear 58 is provided coaxially with the worm wheel 55 to the right of the worm wheel 55. The diameter of the small gear 58 is smaller than the diameter of the worm wheel 55.

A second gear 61 that meshes with the pinion gear 58 is provided to the right of the pinion gear 58. The second gear 61 meshes with the lower part of the pinion gear 58. In this embodiment, the second gear 61 is a sector gear that is fan-shaped.

The rotating device 8 further includes a transmission shaft 62 that is rotatably supported by the device frame 44 and extends in the left-right direction and is driven by the worm wheel 55. In this embodiment, the transmission shaft 62 is integral with the second gear 61 that is connected to the worm wheel 55 via a reduction mechanism 59. The transmission shaft 62 extends rightward from the center of the second gear 61 inside the cylindrical portion 44d of the device frame 44. The tip of the transmission shaft 62 is located to the right of the tip of the cylindrical portion 44d. The tip of the transmission shaft 62 is located approximately in the center in the left-right direction. The worm 54 (and the output shaft 50 of the electric motor 45) and the transmission shaft 62 of the second gear 61 are perpendicular to each other. In other words, the transmission shaft 62 of the second gear 61 and the rotation axis 56 of the worm wheel 55 are parallel to each other.

As shown in Figures 1 and 2, the rotation device 8 is provided between the traveling frame 3a and the working frame 3b and further includes a link mechanism 64 driven by a transmission shaft 62. The link mechanism 64 includes a drive arm 65 connected to the transmission shaft 62, and a drive link 66 having a free end of the drive arm 65 and an end pivoted to a support bracket 39 connected to the rear member 38.

Next, the rotational operation of the snow blower 1 will be described in detail with reference to Figures 6 to 8.

When the worker inputs a rotation operation in the upward or downward direction to the rotation switch 24 of the input device 21, the electric motor 45 of the rotation device 8 rotates in the input direction. The rotation of the electric motor 45 is transmitted to the output shaft 50, and the output shaft 50 and the worm 54 rotate integrally. The rotation of the worm 54 is transmitted to the second gear 61 via the worm wheel 55 and the reduction mechanism 59, and the second gear 61 and the transmission shaft 62 rotate integrally. As a result, the link mechanism 64 connected to the transmission shaft 62 is driven, and the working frame 3b can be rotated around the drive shaft 19 relative to the traveling frame 3a.

As shown in FIG. 6, the second gear 61 can rotate within the gear chamber 46 defined by the device frame 44 between a first position (position shown by solid line) where it abuts against a first portion 68 of the device frame 44 in one direction of rotation, and a second position (position shown by imaginary line) where it abuts against a second portion 69 of the device frame 44 in the other direction of rotation. When the second gear 61 is in the first position, the height of the working section (blower device 6 and auger device 7) is at its highest, as shown in FIG. 8, and when the second gear 61 is in the second position, the height of the working section (blower device 6 and auger device 7) is at its lowest, as shown in FIG. 8.

Next, referring to Figure 9, the relationship between the rotation angle of the second gear 61, the current of the electric motor 45, and the torque of the electric motor 45 will be described in detail.

In FIG. 9, at an initial time T0, the second gear 61 is positioned at an intermediate position between the first position and the second position. From time T0 to time T1, the second gear 61 rotates from the intermediate position toward the first position. At this time, the electric motor 45 is driven by a relatively weak positive current value. After that, the second gear 61 hits the first part 68 of the device frame 44 in one of the rotation directions (time T1). At this time, the current supplied to the electric motor 45 increases significantly in the positive direction, and the torque applied to the second gear 61 increases significantly. When the current value exceeds a certain value for a predetermined time, the supply of current to the electric motor 45 is stopped, and the electric motor 45 stops operating (time T1').

From time T2 to time T3, the second gear 61 rotates from the first position to the second position. At this time, the electric motor 45 is driven by a relatively weak negative current value. After that, the second gear 61 hits the second part 69 of the device frame 44 in the other direction of rotation (time T3). At this time, the current supplied to the electric motor 45 increases significantly in the negative direction, and the torque applied to the second gear 61 increases significantly. If the current value exceeds a certain value for a predetermined time, the supply of current to the electric motor 45 is stopped, and the electric motor 45 stops operating (time T3'). This makes it possible to omit the brake function in the electric motor 45, and therefore makes it possible to make the rotating device 8 more compact.

Next, the effects of the snow blower 1 according to this embodiment will be described in detail.

In the rotating device 8 of this embodiment, the worm 54 and the transmission shaft 62 of the second gear 61 are perpendicular to each other, so the gear train in the gear chamber 46 can be arranged compactly. This makes the rotating device 8 more compact. In addition, the second gear 61 of this embodiment is a sector gear with a fan shape, so the rotating device 8 is even more compact.

The transmission shaft 62 rotates through a reduction mechanism 59 including a small gear 58 that is integral with the worm wheel 55, so that a further reduction ratio can be obtained between the output shaft 50 and the transmission shaft 62. This makes it possible to increase the rotational speed of the electric motor 45, and even if the electric motor 45 is relatively small, it can output a relatively large torque.

The support bracket 39 has a generally L-shape and is connected to the rear and upper surfaces of the rear member 38, which increases the rigidity of the link mechanism 64 in the forward direction.

In addition, the worm 54 and worm wheel 55 in this embodiment are configured so that the worm wheel 55 does not rotate the worm 54 due to the self-locking phenomenon. This allows the brake function of the electric motor 45 to be omitted, making the rotating device 8 even more compact.

This concludes the explanation of the specific embodiment, but the present invention is not limited to the above embodiment and can be modified in a wide range of ways. For example, the rotating device 8 may not have the reduction mechanism 59 and the second gear 61, and the transmission shaft 62 may extend from the center of the worm wheel 55.

1: Snowplow 3: Machine body 3a: Traveling frame 3b: Working frame 4: Traveling device 8: Rotating device 15: Driving wheel 16: Driven wheel 19: Driving shaft 37: Side member 38: Rear member 39: Support bracket 44: Device frame 45: Electric motor 46: Gear chamber 50: Output shaft 51: Electric motor main body 52: Flange portion 54: Worm 55: Worm wheel 56: Rotating shaft 58: Pinion 59: Reduction mechanism 61: Second gear 62: Transmission shaft 64: Link mechanism 65: Driving arm 66: Driving link 68: First portion 69: Second portion 74: First breather opening 77: Second breather opening

Claims (7)

A work machine,
A traveling frame supporting left and right traveling parts each including a driving wheel and a driven wheel;
a working frame that is rotatably provided on the traveling frame with the axle of the drive wheel as a rotation center and supports a working unit for performing a predetermined work;
A drive source for driving the working unit and the traveling unit;
a rotation device interposed between the traveling frame and the work frame for rotating the work frame around the rotation center relative to the traveling frame,
The rotating device is
An apparatus frame;
an electric motor fixed to the device frame;
a worm attached to an output shaft of the electric motor;
a worm wheel rotatably supported by the device frame and meshing with the worm;
a transmission shaft that is rotatably supported by the device frame and driven by the worm wheel, the transmission shaft extending in the left-right direction;
a link mechanism provided between the traveling frame and the work frame and driven by the transmission shaft. The work machine according to claim 1, in which the worm and the transmission shaft are perpendicular to each other. The transmission shaft is integrally provided with a second gear connected to the worm wheel via a reduction mechanism,
the reduction mechanism includes a small gear integrally provided on the worm wheel,
3. The working machine according to claim 1, wherein the transmission shaft of the second gear is parallel to the rotation axis of the worm wheel. The work machine according to any one of claims 3, wherein the second gear is a sector gear having a fan-shaped configuration. the machine frame defines a gear chamber housing a gear train connecting the electric motor to the linkage;
5. The work machine according to claim 4, wherein the second gear is rotatable between a first position where it abuts against a first portion of the equipment frame in one direction of rotation and a second position where it abuts against a second portion of the equipment frame in the other direction of rotation. The work machine according to claim 5, wherein the device frame is formed with a breather opening that connects the gear chamber to the outside. the traveling frame includes left and right side members extending in a front-rear direction, a rear member extending in the left-right direction and connecting rear portions of the side members to each other, and a substantially L-shaped support bracket connected to a rear surface and an upper surface of the rear member,
The working machine according to any one of claims 1 to 6, wherein the link mechanism includes a drive arm coupled to the transmission shaft, and a drive link having a free end of the drive arm and an end pivotally supported on the support bracket.

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