Patent Description:
Specifically, the invention relates to a robotic lawn mower of the generic type defined in the generic part of claim <NUM> attached.

Document <CIT> discloses a robotic lawn mower of the generic type as defined above. Specifically, this document discloses a work machine embodied as a lawn mower and comprising: a power unit; a work unit embodied as a mowing member driven by the power unit; an ejection passageway for ejecting an object to be worked upon that has been acquired by rotation of the work unit; and a control unit which controls the power unit. The work unit may be elevated relative to the work machine by an elevating device.

A lawn mower is one of commonly used garden tools, which is mainly used for mowing all kinds of lawns. With the improvement of people's requirements for greening level and the progress of science and technology, the technological content of the lawn mower is constantly improved, and it is developing towards a direction of being more intelligent and environmentally friendly. Compared with a traditional lawn mower, robotic lawn mowers can run autonomously and complete mowing according to a planned path, which can save a lot of labor, reduce the cost of lawn maintenance and improve labor efficiency. Moreover, they use electric energy and scientifically plan a path, thereby reducing repetitive work and saving energy.

At present, most robotic lawn mowers can usually move the height of their mowing systems up and down in order to achieve different mowing heights. However, structures of an adjusting mechanism and components adjusted by the adjusting mechanism of the mowing systems are relatively complex, the stability of the robotic lawn mowers is poor, and the structures are complex, and the stability is poor during adjusting.

According to the invention there is provided a robotic lawn mower defined in claim <NUM> attached. Preferred embodiments of the invention are defined in dependent claims attached.

A lawn mower <NUM> of a first example shown in <FIG> is used to mow vegetation such as lawns and weeds. In this example, the lawn mower <NUM> is a robotic lawn mower that does not need to be pushed by a user, and the robotic lawn mower can automatically mow the lawns without being operating by the user. The lawn mower can also be a push-type lawn mower. For the push-type lawn mower, the user usually stands behind the push-type lawn mower, and the user pushes a handle of the push-type lawn mower to push it to walk on a ground. Alternatively, the lawn mower may also be a riding lawn mower. For the riding lawn mower, the user rides on a seat of the riding lawn mower to operate it to walk on the ground.

As shown in <FIG> and <FIG>, the lawn mower <NUM> includes a mowing system <NUM>, a working assembly <NUM>, a control assembly, an energy source device <NUM> and a housing <NUM>. The mowing system <NUM> is used to implement a mowing function of the lawn mower <NUM>. The working assembly <NUM> includes a working wheel <NUM> for driving the lawn mower <NUM> to walk on the ground. The control assembly is used to control electrical equipment in the lawn mower <NUM> to display intelligent performances of the lawn mower <NUM>. The energy source device <NUM> is used to provide energy source for the mowing system <NUM>, the working assembly <NUM>, and the control assembly. In this example, the energy source device <NUM> is a power source device, and the power source device may include a battery pack <NUM> installed to the housing <NUM>. The housing <NUM> is used to support the mowing system <NUM>, the control assembly and the energy source device <NUM>. The walking assembly <NUM> is installed to the housing <NUM> and supports the housing <NUM>.

The mowing system <NUM> includes a driving mechanism <NUM>, a cutting assembly <NUM>, and a height adjusting mechanism <NUM>. The driving mechanism <NUM> includes a prime mover for outputting power. The cutting assembly <NUM> includes a mounting shaft <NUM> and a mowing member <NUM>. The mounting shaft <NUM> is used to drive the mowing member <NUM> to rotate about a first axis <NUM> to realize the mowing function. The mowing member <NUM> may be a blade for cutting grass. The height adjusting mechanism <NUM> can adjust the height of the mowing member <NUM> relative to the housing <NUM> in the first axis <NUM>, so that the lawn mower <NUM> has different cutting heights. For example, the height adjusting mechanism <NUM> can adjust the cutting assembly <NUM> to move the mowing member <NUM> to a first height and a second height. When the mowing member <NUM> is at the first height, the mowing member <NUM> is closer to the ground, so that more grass on the ground can be cut. When the mowing member <NUM> is at the second height, the mowing member <NUM> is far away from the ground, so that less grass on the ground can be cut.

In this example, the height adjusting mechanism <NUM> can drive the mounting shaft <NUM> and the mowing member <NUM> mounted on the mounting shaft <NUM> to move up and down along the first axis <NUM>. When the height adjusting mechanism <NUM> adjusts the mounting shaft <NUM> to move up and down, a position of the prime mover relative to the housing <NUM> in the first axis <NUM> remains fixed. In this way, the height adjusting mechanism <NUM> drives the cutting assembly <NUM> to move up and down along the first axis <NUM>, but does not drive the prime mover to move up and down synchronously with the cutting assembly <NUM>, so that a total number of parts driven by the height adjusting mechanism <NUM> that can move up and down in the first axis <NUM> synchronously with the mowing member <NUM> is small. A total weight of the parts is also relatively small, thereby improving the comfort of operating of the height adjusting mechanism <NUM> and also improving the stability of the height adjusting mechanism <NUM>. A weight of loads driven by the height adjusting mechanism <NUM> is also relatively small, thereby prolonging the service life of the height adjusting mechanism <NUM>. In addition, the housing <NUM> is formed with or connected with a mounting structure <NUM>. Because the prime mover does not move up and down with the cutting assembly <NUM>, so that the prime mover can be fixedly installed to the mounting structure <NUM>, thereby improving the reliability of the prime mover and reducing the vibration generated by the prime mover during the operation of the lawn mower <NUM>, thereby prolonging the service life of the lawn mower <NUM>. Furthermore, the mounting shaft <NUM> and the mowing member <NUM> can be driven by the height adjusting mechanism <NUM> at the same time to move up and down in the first axis <NUM>, so that the mowing member <NUM> is stably mounted to the mounting shaft <NUM>, improving the reliability of the cutting assembly <NUM>. Especially for the robotic lawn mower, the size of the robotic lawn mower is relatively small. If the driving mechanism <NUM> also moves up and down along with the cutting assembly <NUM>, the robotic lawn mower needs a larger space for the driving mechanism <NUM> and the cutting assembly <NUM> to move, which is not conducive to the miniaturization of the robotic lawn mower. In this example, the driving mechanism <NUM> does not move with the cutting assembly <NUM>, so that the internal structure of the robotic lawn mower is relatively compact, thereby facilitating the miniaturization of the robotic lawn mower.

The prime mover includes a driving shaft <NUM> for outputting power and the driving shaft <NUM> is the prime mover shaft of the prime mover. In this example, the prime mover is an electric motor <NUM>, the electric motor <NUM> includes a stator assembly and a rotor assembly, the rotor assembly also includes a rotor shaft, and the rotor shaft is the driving shaft <NUM> for outputting power of the electric motor <NUM>. When the height adjusting mechanism <NUM> drives the mounting shaft <NUM> and the mowing member <NUM> to move up and down along the first axis <NUM>, the position of the driving shaft <NUM> relative to the housing <NUM> in the first axis <NUM> remains constant. In the present example, the driving shaft <NUM> is arranged along the first axis <NUM>. The driving shaft <NUM> is also coaxial with the mounting shaft <NUM>. The driving shaft <NUM> is provided with a first mounting hole 1111a extending along the first axis <NUM>, the first mounting hole 1111a penetrates the driving shaft <NUM> along the first axis <NUM>, and the mounting shaft <NUM> is inserted into or passes through the first mounting hole 1111a. When the prime mover is in operation, the driving shaft <NUM> can rotate around the first axis <NUM>, and the driving shaft <NUM> transmits power to the mounting shaft <NUM> to drive the mounting shaft <NUM> to rotate around the first axis <NUM>. The mounting shaft <NUM> can also slide up and down along the first axis <NUM> relative to the driving shaft <NUM>. Specifically, as shown in <FIG>, the driving shaft <NUM> is provided with a driving portion formed on a hole wall of the first mounting hole 1111a, the driving portion drives the mounting shaft <NUM> to rotate synchronously with the driving shaft <NUM>, and the driving portion allows the mounting shaft <NUM> to slide up and down relative to the driving shaft <NUM>. In this example, the driving portion is directly formed on the hole wall of the mounting hole 1111a and the driving portion is a transmission plane parallel to the first axis <NUM>. It can be understood that in some other examples, a mounting hole of a driving shaft can also be provided with a driving member, the driving member may be a bushing, the bushing is fixedly connected with the driving shaft, and the bushing forms a driving hole, and a hole wall of the driving hole forms a driving portion that can drive a mounting shaft to rotate with the driving shaft, and the mounting shaft passes through the driving hole.

In the present example, the cutting assembly <NUM> also includes a mounting member for mounting the mowing member <NUM> to the mounting shaft <NUM>. The mounting member is a disc, the mowing member <NUM> is a blade mounted on the disc, and the blade also can rotate relative the disc. The disc is fixed to a preset position on the mounting shaft <NUM> through fasteners, and there is only one preset position. That is to say, the position of the disc relative to the mounting shaft <NUM> in the first axis <NUM> is not adjustable, and the position of the disc relative to the mounting shaft <NUM> in the first axis <NUM> is fixed. In this way, the disc can be more stably installed to the mounting shaft <NUM>, so as to prevent the disc from loosening relative to the mounting shaft <NUM>.

The height adjusting mechanism <NUM> includes an operating member and an adjusting assembly <NUM>. The operating member is used for the user to operate to control cutting heights of the cutting assembly <NUM>. In this example, the operating member is a knob <NUM> that can be turned by the user. The knob <NUM> may be arranged below the housing <NUM> or above the housing <NUM>. In other examples, an operating element may also be an operating button. The lawn mower <NUM> further includes a display screen <NUM>, and the operating member may be a touch button on the display screen <NUM>, and the display screen <NUM> is a touch screen.

The adjusting assembly <NUM> includes an adjusting member <NUM> and a mounting bracket <NUM>. The mounting bracket <NUM> is composed of two parts. The adjusting member <NUM> is connected to the operating member, and the mounting bracket <NUM> is used for mounting the mounting shaft <NUM>. When the user operates the knob <NUM>, the adjusting member <NUM> adjusts the mounting bracket <NUM> to move along the first axis <NUM> or a direction parallel to the first axis <NUM>, and the mounting bracket <NUM> drives a whole of the mounting shaft <NUM> and the mowing member <NUM> along the first axis <NUM>, so that the lawn mower <NUM> has different cutting heights.

The adjusting member <NUM> can rotate around a rotation axis, and the adjusting member <NUM> and the mounting bracket <NUM> form a transmission fit that can convert the rotation of the adjusting member <NUM> into a sliding movement of the mounting bracket <NUM> along the first axis <NUM>. The transmission fit may be a direct fit between the adjusting member <NUM> and the mounting bracket <NUM>, or an indirect fit in which a switching structure is provided between the adjusting member <NUM> and the mounting bracket <NUM>. Specifically, the adjusting member <NUM> is a screw rod. A first thread is formed on the screw rod, and a second thread that matches the first thread is formed on the mounting bracket <NUM>. The rotation of the mounting bracket <NUM> about the first axis <NUM> is restricted, that is, the mounting bracket <NUM> cannot rotate about the first axis <NUM>. In this way, when the adjusting member <NUM> rotates with the knob <NUM>, the adjusting member <NUM> will drive the mounting bracket <NUM> to move along the first axis <NUM> under the cooperation of the first thread and the second thread. The screw rod is mounted to the mounting structure <NUM> of the housing <NUM>.

As shown in <FIG>, the mounting bracket <NUM> is formed with a second mounting hole 1322b extending along the first axis <NUM>, and the mounting shaft <NUM> passes through the second mounting hole 1322b. The second mounting hole 1322b is also recessed along a radial direction perpendicular to the first axis <NUM> to form a groove 1322c. The adjusting assembly <NUM> further includes a bearing <NUM>, the bearing <NUM> is installed in the groove 1322c, and the bearing <NUM> can move synchronously with the mounting bracket <NUM> along the first axis <NUM>. A groove wall of the groove 1322c is formed with a first limiting portion 1322d, and the first limiting portion 1322d can restrict the bearing <NUM> from separating from the mounting bracket <NUM> along the first axis <NUM>. The bearing <NUM> also supports the mounting shaft <NUM>, an inner ring of the bearing <NUM> can be fixedly connected to the mounting shaft <NUM>, and an outer ring of the bearing <NUM> can be fixedly connected to the groove wall of the groove 1322c. In this example, the inner ring of the bearing <NUM> can be interference fit with the mounting shaft <NUM>, and the outer ring of the bearing <NUM> can be interference fit with the groove wall of the groove 1322c.

In the present example, the mounting shaft <NUM> is formed with or connected with a second limiting portion <NUM>, and the second limiting portion <NUM> can limit the bearing <NUM> from disengaging from the mounting shaft <NUM> along the first axis <NUM>. In the present example, the second limiting portion <NUM> is a pair of annular protrusions formed on the mounting shaft <NUM>, and the bearing <NUM> is arranged between the pair of annular protrusions. In other examples, a second limiting portion may also be a clamp ring provided on a mounting shaft.

The height adjusting mechanism <NUM> further includes a sliding rail for restricting the rotation of the mounting bracket <NUM>, and the sliding rail is installed on the housing <NUM> along a direction parallel to the first axis <NUM>. One side of the mounting bracket <NUM> is used as a sliding block to cooperate with the sliding rail. The sliding rail is formed on the housing <NUM>, or the sliding rail is formed of a part fixed relative to the housing <NUM>. The sliding rail limits the rotation of the mounting bracket <NUM> around the first axis <NUM> and allows the mounting bracket to slide along the sliding rail in the first axis <NUM>. One end of the screw rod is fixed relative to the housing <NUM>, the screw rod can only rotate around the axis of the screw rod, and the other end of the screw rod passes through and is fixedly connected with the knob <NUM>, which can drive the screw rod to rotate when the knob <NUM> rotates.

When the user operates the knob <NUM>, the screw rod follows the knob <NUM> to rotate. Because the mounting bracket <NUM> is matched with the screw rod, and the other side of the mounting bracket <NUM> is fitted in the sliding rail and cannot rotate and move horizontally, the mounting bracket <NUM> can move up and down along the slid sliding rail under the rotation of the screw rod.

Because the bearing <NUM> is fixed on the mounting bracket <NUM>, the bearing <NUM> has a tendency to move up and down following the mounting bracket <NUM>, and thus has a tendency to move relative to the mounting shaft <NUM>. Since the mounting shaft <NUM> is provided with a stopper that restricts the relative movement of the bearing <NUM> and the mounting shaft <NUM>, the bearing <NUM> will drive the mounting shaft <NUM> to move up and down when the bearing <NUM> is driven by the mounting bracket <NUM>.

The mounting shaft <NUM> cooperates with the driving shaft <NUM> of the driving mechanism <NUM>. But the mounting shaft <NUM> cannot drive the driving shaft <NUM> to move up and down, thus cannot drive the driving mechanism <NUM> to move up and down.

Therefore, the height adjusting mechanism <NUM> only adjusts the height of the mounting shaft <NUM> and does not adjust the height of other components.

<FIG> shows the internal structure of a lawn mower of a second example. In this example, the lawn mower may also be a robotic lawn mower. The lawn mower includes a working assembly, a control assembly, and a power source device which are substantially the same as that in the lawn mower <NUM> in the first example. The lawn mower of this example further includes a mowing system 20a and a housing for mounting the mowing system 20a, and the housing includes a mounting structure <NUM>. The mowing system 20a includes a cutting assembly <NUM> and a height adjusting mechanism <NUM> that are basically the same as that in the lawn mower <NUM> of the first example. The main difference between this example and the first example is that the mowing system 20a includes a driving mechanism <NUM> that is different from that in the first example. The driving mechanism <NUM> includes a prime mover <NUM> and a transmitting assembly <NUM> for realizing a power transmission between the prime mover <NUM> and the cutting assembly. In this example, because the driving mechanism <NUM> is different from the first example and the driving mechanism <NUM> is mounted to the housing, the housing also includes another mounting structure <NUM> for mounting the driving mechanism <NUM>. The following mainly introduces the differences between this example and the first example, and the parts of this example with the same as the first example will not be described in detail.

As shown in <FIG>, the height adjusting mechanism <NUM> can adjust a whole of a mounting shaft <NUM> and a mowing member <NUM> to move up and down along a first axis <NUM>, so that the lawn mower has different cutting heights.

In this example, the prime mover <NUM> includes a prime mover shaft <NUM> that can rotate about a second axis <NUM>. The transmitting assembly <NUM> is used to transmit a power output by the prime mover shaft <NUM> to the mounting shaft <NUM>.

In this example, the transmitting assembly <NUM> is mounted to the mounting structure <NUM> of the housing. The transmitting assembly <NUM> includes a driving shaft for driving the mounting shaft <NUM> to rotate, which drives the mounting shaft <NUM> to rotate synchronously and allows the mounting shaft <NUM> to move up and down in the first axis <NUM> relative to it. Here, the driving shaft is considered as a part of the transmitting assembly <NUM>, and the driving shaft is a power output member of the transmitting assembly <NUM>. Of course, it can be considered that the driving shaft is not part of the transmitting assembly <NUM>, but that the transmitting assembly <NUM> is used to transfer a power between the prime mover <NUM> and the driving shaft. In this example, the driving shaft is a first driving wheel <NUM>, and the transmitting assembly <NUM> further includes a second driving wheel <NUM> and a driving belt <NUM>. The driving belt <NUM> is a synchronous belt, the first driving wheel <NUM> and the second driving wheel <NUM> are synchronous belt wheels, and a torque transmission of the transmitting assembly <NUM> is constant speed transmission. In other words, the transmitting assembly <NUM> only transmits a torque without changing the speed, so that the speed of the mounting shaft <NUM> is the same as that of the prime mover shaft <NUM>. In other examples, a transmitting assembly can also change the speed transmitted from the prime mover shaft to the mounting shaft so that the speed of the mounting shaft is different from that of the prime mover shaft.

In some other examples, the transmitting assembly may be one or a combination of two or more of belt transmission, rope transmission, friction wheel transmission, gear transmission, chain transmission, screw transmission, or harmonic transmission.

By providing the transmitting assembly <NUM>, the prime mover <NUM> and the mounting shaft <NUM> are not arranged on the same axis, an overall size of the driving mechanism <NUM> and the cutting assembly <NUM> in a height direction of the housing can be reduced, thereby facilitating the miniaturization of the lawn mower. Moreover, in the present example, the prime mover <NUM> is a motor, and the transmitting assembly <NUM> is provided so that the electric motor can be a conventional electric motor in the prior art, which reduces the design and production cost of the motor and can also improve the structural strength and reliability of the motor. Furthermore, the transmitting assembly <NUM> is provided so that the cutting assembly <NUM> can be separated from the driving mechanism <NUM>, thereby facilitating maintenance of the driving mechanism <NUM> and the cutting assembly <NUM> separately.

Specifically, the second driving wheel <NUM> is fixedly connected to the prime mover shaft <NUM>, and the first driving wheel <NUM> is formed with a driving portion 221a. The driving portion 221a can output torque to the mounting shaft <NUM> to drive the mounting shaft <NUM> to rotate synchronously with the first driving wheel <NUM>. The driving portion 221a also allows the mounting shaft <NUM> to move up and down along the first axis <NUM>. In this way, when the user operates an operating member <NUM>, the height adjusting mechanism <NUM> can adjust a whole of the mounting shaft <NUM> and the cutting member <NUM> to move up and down along the first axis <NUM> relative to the transmitting assembly <NUM>, thereby enabling the lawn mower to have different cutting heights.

In the present example, the height adjusting mechanism <NUM> only drives the cutting assembly <NUM> to move up and down in the first axis <NUM>, while the prime mover <NUM> and the transmitting assembly <NUM> are kept constant relative to the housing in the first axis <NUM>. A total number of parts driven by the height adjusting mechanism <NUM> that can move up and down in the first axis <NUM> synchronously with the mowing member <NUM> is small, and a total weight of the parts is also relatively small, thereby improving the comfort of operation of the height adjusting mechanism <NUM> and improving the stability of the height adjusting mechanism <NUM>. The weight of loads driven by the height adjusting mechanism <NUM> is also relatively small, thereby prolonging the service life of the height adjusting mechanism <NUM>. In addition, since the prime mover <NUM> and the transmitting assembly <NUM> do not move up and down together with the cutting assembly <NUM>, the prime mover <NUM> and the transmitting assembly <NUM> can be mounted to the mounting structure <NUM> of the housing, thereby improving the reliability of the prime mover <NUM> and the transmitting assembly <NUM>, reducing the vibration generated by the prime mover <NUM> and the transmitting assembly <NUM> during the operation of the lawn mower, thereby extending the service life of the lawn mower. Furthermore, the mounting shaft <NUM> and the mowing member <NUM> can be driven by the height adjusting mechanism <NUM> to move up and down in the first axis <NUM>, so that the mowing member <NUM> is stably mounted to the mounting shaft <NUM>, which improves the reliability of the cutting assembly <NUM>.

In the present example, the fit between the first driving wheel <NUM> and the mounting shaft <NUM> is clearance fit. When the mounting shaft <NUM> moves up and down under an external force, because the mounting shaft <NUM> is in the clearance fit with the first driving wheel <NUM>, the mounting shaft <NUM> does not drive the first driving wheel <NUM> and the driving belt <NUM> matched with the first driving wheel <NUM> to move up and down, so the prime mover <NUM> dose not move with the mounting shaft <NUM> when the mounting shaft <NUM> moves up and down.

The driving mechanism <NUM> can be assembled at any position in the housing under a premise of ensuring that the prime mover shaft <NUM> can transmit torque to the mounting shaft <NUM> through the transmitting assembly <NUM>, so that it can also be assembled at a more reasonable position according to the position of a center of gravity of the lawn mower and the arrangement of internal structures.

The second axis <NUM> on which the prime mover shaft <NUM> rotates does not overlap with the first axis <NUM> on which the mounting shaft <NUM> rotates.

Preferably, the first axis <NUM> and the second axis <NUM> are parallel to each other and spaced apart by a distance. The second axis <NUM> is parallel to and not coincident with the first axis <NUM>. Alternatively, in some other examples, a second axis and a first axis may be perpendicular to each other, or the second axis may be inclined relative to the first axis.

Claim 1:
A robotic lawn mower (<NUM>), comprising:
a mowing system (<NUM>) for mowing grass;
a housing (<NUM>) configured to support the mowing system (<NUM>);
a working assembly (<NUM>) comprising a working wheel (<NUM>) configured to support the housing (<NUM>) to drive the robotic lawn mower (<NUM>) to walk on a ground; and
an energy source device (<NUM>) used to provide energy source;
wherein the mowing system (<NUM>) comprises:
a cutting assembly (<NUM>) comprising a mowing member (<NUM>) for cutting the grass and a mounting shaft (<NUM>) for mounting the mowing member (<NUM>), wherein the mounting shaft (<NUM>) is capable of rotating about a first axis (<NUM>) relative to the housing (<NUM>);
a driving mechanism (<NUM>) comprising an electric motor (<NUM>), the electric motor (<NUM>) comprising a stator assembly and a rotor assembly, the rotor assembly comprising a driving shaft (<NUM>) for driving the cutting assembly (<NUM>) to rotate; and
a height adjusting mechanism (<NUM>) for adjusting the movement of the cutting assembly (<NUM>) along the first axis (<NUM>) to achieve different cutting heights of the mowing member (<NUM>), characterized in that
the driving shaft (<NUM>) is provided with a mounting hole (1111a) and the mounting shaft (<NUM>) passes through the mounting hole (1111a);
the driving shaft (<NUM>) is formed with a driving portion for driving the mounting shaft (<NUM>) to rotate synchronously with the driving shaft (<NUM>) and the driving portion allows the mounting shaft (<NUM>) to move relative to the driving shaft (<NUM>) along the first axis (<NUM>); and
when the height adjusting mechanism (<NUM>) adjusts the cutting assembly (<NUM>) to move along the first axis (<NUM>), the mounting shaft (<NUM>) moves relative to the driving shaft (<NUM>) along the first axis (<NUM>).