JP2020185831A - Self-propelled working machine - Google Patents

Abstract

To suppress occurrence of an unintended regenerative current by a motor.SOLUTION: A self-propelled working machine includes a vehicle body, a handle which is provided on the vehicle body and is gripped by a user, wheels which are rotatably provided on the vehicle body, a motor which is provided on the vehicle body and drives the wheels, and a lock mechanism which is provided between the motor and the wheels and outputs rotation of the motor to the wheels. The lock mechanism includes an input shaft connected to the motor and an output shaft connected to the wheels, and inhibits or suppresses rotation of the output shaft when a rotational speed of the output shaft is higher than a rotational speed of the input shaft.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a self-propelled work machine, and more particularly to a hand-push type self-propelled work machine such as a hand-push trolley and a hand-push lawnmower.

Patent Document 1 discloses a lawnmower which is an example of a self-propelled working machine. This lawnmower includes a vehicle body, a handle provided on the vehicle body, wheels rotatably provided on the vehicle body, and a motor provided on the vehicle body to drive the wheels.

JP-A-2017-163921

In a self-propelled work machine, the rotation of the motor is usually transmitted to the wheels. However, when the self-propelled work machine is on an inclined surface or when the user applies a force to the self-propelled work machine, the rotation of the wheels is transferred to the motor when the self-propelled work machine is moved by an external force. May be transmitted. In this case, a regenerative current may be generated from the motor, which may damage the electric circuit system of the self-propelled work machine. The present specification provides techniques that can solve or reduce such problems.

The self-propelled work machine disclosed in the present specification includes a vehicle body, a handle provided on the vehicle body and gripped by a user, wheels rotatably provided on the vehicle body, and a motor provided on the vehicle body to drive the wheels. And a lock mechanism provided between the motor and the wheel and outputting the rotation of the motor to the wheel. The lock mechanism includes an input shaft connected to the motor and an output shaft connected to the wheels, and prohibits or suppresses the rotation of the output shaft when the rotation speed of the output shaft exceeds the rotation speed of the input shaft.

In the self-propelled work machine described above, a lock mechanism is provided between the motor and the wheels. The lock mechanism includes an input shaft connected to a motor and an output shaft connected to wheels, and prohibits or suppresses the rotation of the output shaft when the rotation speed of the output shaft exceeds the rotation speed of the input shaft. It is configured as follows. Therefore, even when the self-propelled work machine is moved by an external force, it is possible to prohibit or suppress the rotation of the wheels from being transmitted to the motor. As a result, the generation of unintended regenerative current by the motor is prohibited or suppressed.

The appearance of the lawn mower 10 of the embodiment is shown. The block diagram which shows the structure of the lawnmower 10 of an Example. In the figure, solid arrows indicate the flow of electric power, and white arrows indicate the flow of mechanical power. The traveling unit 40 is shown. An exploded view of the lock mechanism 44 together with the planetary gear mechanism 46a is shown. An exploded view of the lock mechanism 44 from another viewpoint is shown. A cross-sectional view perpendicular to the axial direction of the lock mechanism 44 is shown. FIG. 5 is a cross-sectional view perpendicular to the axial direction of the lock mechanism 44, showing how the rotation of the input shaft 60 is transmitted to the output shaft 62. FIG. 5 is a cross-sectional view perpendicular to the axial direction of the lock mechanism 44, showing how the rotation of the output shaft 62 is prohibited from being transmitted to the input shaft 60.

In one embodiment of the present technology, the locking mechanism may further include a fixing member fixed to the vehicle body. In this case, the lock mechanism may be configured to apply a braking force from the fixing member to the output shaft when the rotation speed of the output shaft exceeds the rotation speed of the input shaft.

In the above embodiment, the locking mechanism may further include a locking member located between the fixing member and the output shaft. In this case, the locking mechanism may be configured to apply a braking force from the fixing member to the output shaft via the locking member.

In the above-described embodiment, the lock member may have a cylindrical shape or a spherical shape. In this case, the cylindrical or spherical lock member may be configured to rotate with respect to the fixed member together with the input shaft and the output shaft when the rotation speed of the input shaft exceeds the rotation speed of the output shaft. ..

In one embodiment of the present technology, the self-propelled work machine may further include a speed reducer provided between the lock mechanism and the wheels. According to such a configuration, since the lock mechanism is located between the motor and the speed reducer (that is, located on the input side of the speed reducer), the torque acting on the lock mechanism can be reduced.

In one embodiment of the present technology, the self-propelled working machine may further include a clutch provided between the locking mechanism and the wheels to selectively connect and disconnect between the locking mechanism and the wheels. According to such a configuration, the clutch disengages the connection between the lock mechanism and the wheel to temporarily allow the movement of the self-propelled work machine by an external force (for example, gravity or user force). Can be done.

In the above-described embodiment, the clutch may have, for example, one or more of a meshing clutch (for example, a dog clutch), a one-way clutch, a friction clutch, a centrifugal clutch, and an electromagnetic clutch. However, the clutch in the present technology is not limited to these.

Hereinafter, typical and non-limiting specific examples of the present invention will be described in detail with reference to the drawings. This detailed description is intended to provide those skilled in the art with details for implementing the preferred examples of the invention and is not intended to limit the scope of the invention. In addition, the additional features and inventions disclosed below may be used separately or together with other features and inventions to provide a further improved self-propelled working machine.

In addition, the combination of features and processes disclosed in the following detailed description is not essential for carrying out the present invention in the broadest sense, and is particularly for explaining a typical specific example of the present invention. It is to be described. Further, various features of the above and below representative examples, as well as various features of those described in the independent and dependent claims, are described herein in providing additional and useful embodiments of the present invention. It does not have to be combined according to the specific examples given or in the order listed.

All features described herein and / or claims are, apart from the constitution of the features described in the examples and / or claims, as a limitation to the disclosure at the time of filing and the specific matters claimed. It is intended to be disclosed individually and independently of each other. In addition, all numerical ranges and statements relating to groups or groups are made with the intention of disclosing their intermediate composition as a limitation to the disclosure at the time of filing and the specific matters claimed.

The lawnmower 10 of the embodiment will be described with reference to the drawings. The lawn mower 10 is an example of a self-propelled work machine, and in particular, an example of a hand-push type self-propelled work machine. That is, the lawnmower 10 is configured so that the progress, stop, speed, direction, and the like are controlled by a user walking with the lawnmower 10.

As shown in FIG. 1, the lawnmower 10 includes a vehicle body 12 and a handle 14 provided on the vehicle body 12. The battery pack 2 is detachably attached to the vehicle body 12. The battery pack 2 is a power source that supplies electric power to the lawnmower 10. As an example, the output voltage of the battery pack 2 is 36 volts. A grass collecting box 24 is attached to the rear part of the vehicle body 12.

The handle 14 is configured to be gripped by the user. The user walks behind the lawnmower 10 while grasping the handle 14, and operates the lawnmower 10 through the handle 14. The handle 14 is provided with a lawn mowing switch 16 and a traveling switch 18. The grass mowing switch 16 and the traveling switch 18 are operating members operated by the user, respectively.

As shown in FIG. 1, the lawnmower 10 includes a plurality of wheels 20, 22. The plurality of wheels 20 and 22 are rotatably provided on the vehicle body 12, respectively. The plurality of wheels 20 and 22 include a pair of driven wheels 20 and a pair of driving wheels 22. The pair of driven wheels 20 are located at the front of the vehicle body 12, and the pair of drive wheels 22 are located at the rear of the vehicle body 12.

As shown in FIGS. 1 and 2, the lawnmower 10 further includes a lawnmower blade 30 and a lawnmower motor 32. The lawn cutting blade 30 is located on the bottom surface of the vehicle body 12 and faces the ground 100. The lawn cutting blade 30 is rotatably provided with respect to the vehicle body 12. The lawn mowing motor 32 is connected to the lawn mowing blade 30 and rotationally drives the lawn mowing blade 30. Electric power is supplied to the lawn mowing motor 32 from the battery pack 2. Although not particularly limited, in the lawnmower 10 of the present embodiment, the lawnmower blade 30 is directly connected to the rotation shaft of the lawnmower motor 32. However, a speed reducer (not shown) may be provided between the lawn mower motor 32 and the lawn mower blade 30. The lawn mower 10 is configured to mow the lawn growing on the ground 100 by rotating the lawn mowing blade 30 by the lawn mowing motor 32.

The lawnmower 10 includes a traveling unit 40. The traveling unit 40 is provided on the vehicle body 12 and is connected to a pair of drive wheels 22. As shown in FIGS. 2 and 3, the traveling unit 40 includes a traveling motor 42, a lock mechanism 44, a speed reducer 46, and a clutch 48. The traveling motor 42 is a prime mover that drives a pair of drive wheels 22. The traveling motor 42 is connected to a pair of drive wheels 22 via a lock mechanism 44, a speed reducer 46, and a clutch 48. As an example, the traveling motor 42 in this embodiment is a three-phase brushless motor. A brushed motor may be adopted as the traveling motor 42.

The lock mechanism 44 is provided between the traveling motor 42 and the speed reducer 46. The lock mechanism 44 outputs the rotation of the traveling motor 42 to the speed reducer 46 (that is, to the pair of drive wheels 22). The lock mechanism 44 will be described in detail later. The speed reducer 46 is provided between the lock mechanism 44 and the clutch 48. The speed reducer 46 amplifies the rotational torque input from the lock mechanism 44 and outputs the torque to the clutch 48. Although not particularly limited, the speed reducer 46 in this embodiment has a planetary gear mechanism 46a and a set of gear trains 46b.

The clutch 48 is provided between the speed reducer 46 and the pair of drive wheels 22. The clutch 48 can selectively connect and disconnect the speed reducer 46 and the pair of drive wheels 22. Although not particularly limited, the clutch 48 in this embodiment has a pair of dog clutches 48a and 48b. One dog clutch 48a is provided between one of the pair of drive wheels 22 and the speed reducer 46, and is connected to one drive wheel 22 via an axle 49a. The other dog clutch 48b is provided between the other of the pair of drive wheels 22 and the speed reducer 46, and is connected to the other drive wheel 22 via an axle 49b. The dog clutches 48a and 48b can be connected to and disconnected from the speed reducer 46 and the drive wheels 22 according to the operation by the user. The clutch 48 may have one or more other types of clutches in place of or in addition to the pair of dog clutches 48a and 48b. In this case, the clutch 48 may have one or more of, for example, a one-way clutch, a friction clutch, a centrifugal clutch, and an electromagnetic clutch.

As shown in FIG. 2, the lawnmower 10 includes a power controller 50. The power controller 50 adjusts the electric power supplied from the battery pack 2 to the lawn mowing motor 32 and the traveling motor 42. A lawn mowing switch 16 and a traveling switch 18 are connected to the power controller 50. The power controller 50 adjusts the electric power supplied from the battery pack 2 to the lawn mowing motor 32 according to the operation applied to the lawn mowing switch 16. Further, the power controller 50 adjusts the electric power supplied from the battery pack 2 to the traveling motor 42 according to the operation applied to the traveling switch 18. As described above, the traveling motor 42 is a three-phase brushless motor. Therefore, the power controller 50 has a built-in inverter circuit that converts the DC power from the battery pack 2 into three-phase AC power.

Next, the locking mechanism 44 will be described with reference to FIGS. 4 to 6. The locking mechanism 44 in this embodiment has the same configuration as the spindle locking mechanism described in JP-A-2007-283471, and the configuration is also described in detail in the publication.

As shown in FIGS. 4 to 6, the lock mechanism 44 includes an input shaft 60, an output shaft 62, a fixing member 64, and two lock members 66. The input shaft 60 is connected to the motor shaft 42a of the traveling motor 42. The output shaft 62 is connected to the sun gear 47 of the planetary gear mechanism 46a. That is, the input shaft 60 is connected to the traveling motor 42, and the output shaft 62 is connected to the pair of drive wheels 22. The fixing member 64 has a ring shape and is fixed to the vehicle body 12. The two locking members 66 are located between the fixing member 64 and the output shaft 62. Each lock member 66 has a cylindrical shape.

The input shaft 60 is provided with four engaging protrusions 60a. The four engaging protrusions 60a project along the axial direction and are located inside the fixing member 64. The four engaging protrusions 60a are arranged along the circumferential direction. Here, the distance between the four engaging protrusions 60a in the circumferential direction may or may not be constant. The output shaft 62 is located inside the fixing member 64, and four engaging protrusions 60a of the input shaft 60 are located around the output shaft 62. The output shaft 62 is provided with two engaging protrusions 62a. Each engaging projection 62a of the output shaft 62 projects radially and is located between two adjacent engaging projections 60a of the input shaft 60. The lock member 66 is located between the output shaft 62 and the fixing member 64 in the radial direction. Further, the lock member 66 is located between two adjacent engaging projections 60a of the input shaft 60 in the circumferential direction.

Two planes 62b are provided on the outer circumference of the output shaft 62 in accordance with the positions of the two lock members 66. That is, each lock member 66 is located between the plane 62b of the output shaft 62 and the fixing member 64. The distance between the plane 62b of the output shaft 62 and the fixing member 64 is larger than the diameter of the lock member 66 at the center of the plane 62b and smaller than the diameter of the lock member 66 at both ends of the plane 62b. As a result, if the lock member 66 is maintained near the center of the plane 62b of the output shaft 62, the output shaft 62 can freely rotate with respect to the fixing member 64. On the other hand, when the lock member 66 moves near both ends of the plane 62b of the output shaft 62, the lock member 66 is engaged between the output shaft 62 and the fixing member 64. As a result, a strong braking force acts on the output shaft 62 from the fixing member 64 via the lock member 66.

As shown in FIG. 7, when the traveling motor 42 rotates the input shaft 60 clockwise, the four engaging protrusions 60a of the input shaft 60 are replaced with the two engaging protrusions 62a and the two locking members of the output shaft 62. Each abuts on 66. As a result, the rotation of the input shaft 60 is transmitted to the output shaft 62. At this time, the two lock members 66 are supported by the engaging projection 60a of the input shaft 60 and maintained near the center of the plane 62b of the output shaft 62. Therefore, the output shaft 62 can freely rotate with respect to the fixing member 64, and rotates together with the two lock members 66 together with the input shaft 60.

On the other hand, as shown in FIG. 8, for example, when the lawnmower 10 is moved by an external force and only the output shaft 62 rotates clockwise, the lock member 66 moves near one end of the plane 62b of the output shaft 62. In this case, since the lock member 66 is engaged between the output shaft 62 and the fixing member 64, a strong braking force acts on the output shaft 62 from the fixing member 64 via the lock member 66. At this time, the engaging projection 62a of the output shaft 62 has not yet come into contact with the engaging projection 60a of the input shaft 60. Therefore, the rotation of the output shaft 62 is prohibited or suppressed from being transmitted to the input shaft 60.

As described above, in the lawnmower 10 of the present embodiment, the lock mechanism 44 is provided between the traveling motor 42 and the drive wheels 22. The lock mechanism 44 includes an input shaft 60 connected to the traveling motor 42 and an output shaft 62 connected to the drive wheels 22, and when the rotation speed of the output shaft 62 exceeds the rotation speed of the input shaft 60. , It is configured to prohibit or suppress the rotation of the output shaft 62. Therefore, even when the lawnmower 10 is moved by an external force, it is prohibited or suppressed that the rotation of the drive wheels 22 is transmitted to the traveling motor 42. As a result, it is possible to prohibit or suppress the generation of an unintended regenerative current by the traveling motor 42, and to avoid damage to the power controller 50, for example.

In the lawnmower 10 of this embodiment, a speed reducer 46 is provided between the lock mechanism 44 and the drive wheels 22. In other words, the lock mechanism 44 is located between the traveling motor 42 and the speed reducer 46 on the input side of the speed reducer 46. According to such a configuration, when the lawnmower 10 is moved by an external force, the torque of rotation of the drive wheels 22 is reduced by the speed reducer 46 and then input to the lock mechanism 44. As a result, the torque acting on the lock mechanism 44 can be reduced.

In the lawnmower 10 of this embodiment, a clutch 48 is provided between the lock mechanism 44 and the drive wheels 22. The clutch 48 can selectively connect and disconnect between the lock mechanism 44 and the drive wheels 22. According to such a configuration, for example, the user can move the lawnmower 10 by his / her own force by releasing the connection between the lock mechanism 44 and the drive wheel 22 by the clutch 48. Even in this case, since the rotation of the drive wheels 22 is not transmitted to the traveling motor 42, the regenerative current is not unintentionally generated by the traveling motor 42.

The specific configuration of the lock mechanism 44 is not limited to that described in this embodiment. The lock mechanism 44 may be configured so as to transmit the rotation of the input shaft 60 to the output shaft 62 and not to transmit the rotation of the output shaft 62 to the input shaft 60. For example, the lock member 66 is not limited to a cylindrical shape, and may have a spherical shape, for example. Alternatively, the shape, arrangement and number of the engaging protrusions 60a of the input shaft 60 and the shape, arrangement and number of the engaging protrusions 62a of the output shaft 62 can be appropriately changed. Further, the flat surface 62b of the output shaft 62 may be curved in a concave shape or a convex shape.

The technique described in this embodiment, particularly the technique related to the traveling unit 40, is not limited to the lawnmower 10, and is various types of hand-pushed self-propelled vehicles such as a push cart, a snowplow, a cultivator, and a floor cleaner. It can be used for type work machines.

2: Battery pack 10: Lawn mowing machine 12: Body 14: Handle 16: Lawn mowing switch 18: Travel switch 20: Driven wheel 22: Drive wheel 24: Grass collecting box 30: Grass cutting blade 32: Lawn mowing motor 40: For traveling Unit 42: Driving motor 42a: Motor shaft 44: Lock mechanism 46: Reducer 48: Clutch 50: Power controller 60: Lock mechanism input shaft 62: Lock mechanism output shaft 64: Lock mechanism fixing member 66: Lock mechanism Lock member 100: Ground

Claims (6)

With the car body
A steering wheel provided on the vehicle body and gripped by the user,
Wheels rotatably provided on the vehicle body and
A motor provided on the vehicle body and driving the wheels,
A lock mechanism provided between the motor and the wheels and outputting the rotation of the motor to the wheels is provided.
The lock mechanism includes an input shaft connected to the motor and an output shaft connected to the wheel, and when the rotation speed of the output shaft exceeds the rotation speed of the input shaft, the output shaft rotates. Prohibit or suppress
Self-propelled work machine. The lock mechanism further includes a fixing member fixed to the vehicle body, and applies a braking force from the fixing member to the output shaft when the rotation speed of the output shaft exceeds the rotation speed of the input shaft. The self-propelled work machine according to 1. The lock mechanism according to claim 2, further comprising a lock member located between the fixing member and the output shaft, and applying the braking force from the fixing member to the output shaft via the lock member. Self-propelled work machine. The self-propelled working machine according to claim 3, wherein the lock member has a cylindrical shape or a spherical shape. The self-propelled work machine according to any one of claims 1 to 3, further comprising a speed reducer provided between the lock mechanism and the wheels. The self-propelled vehicle according to any one of claims 1 to 4, further comprising a clutch provided between the lock mechanism and the wheel and selectively connecting and disconnecting the lock mechanism and the wheel. Running work machine.

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