Patent Description:
In the related art, a chainsaw is a cutting tool mainly used for felling and bucking, which performs a cutting operation on wood through a reciprocating motion of a chain. In the chainsaw, the chain is generally driven by a motor, and since the chain needs to be lubricated or cooled during the reciprocating motion, an oil pump and an oil can need to be disposed inside the chainsaw. The oil pump drives a liquid in the oil can to be transported to the chain via an oil passage to lubricate or cool the chain. However, in practical use, the oil passage may be jammed and thus the chain cannot be fully lubricated or cooled, affecting the cutting operation of an operator.

A chainsaw according to the preamble of claim <NUM> is known from <CIT>.

An object of the present application is to solve or at least alleviate part or all of the preceding problems. Therefore, an object of the present application is to provide a chainsaw with a controller for determining and for releasing a jammed state of a liquid pump.

To achieve the preceding object, the present application adopts the technical solutions below.

A chainsaw according to the invention is defined by the features of claim <NUM>.

Preferred embodiments are defined by the features of the dependent claims.

In some examples, a chainsaw includes a chain, a liquid pump assembly, a motor, and a controller. The chain is used for implementing a cutting operation. The liquid pump assembly includes a liquid pump and a motor. The liquid pump is used for releasing a liquid for lubricating or cooling the chain. The motor is used for at least driving the liquid pump to operate. The controller is electrically connected to at least the motor. The controller is configured to, when the liquid pump is in a jammed state, control the liquid pump assembly to enter a throttling mode in which a supplied amount of the liquid is reduced, and when the liquid pump exits the jammed state, control the liquid pump assembly to exit the throttling mode.

In some examples, a chainsaw includes: a chain for implementing a cutting operation; a first motor for driving the chain to operate; a liquid pump assembly including a liquid pump and a second motor for driving the liquid pump to operate; a temperature detection module for detecting an ambient temperature of the chainsaw; and a controller electrically connected to at least the first motor and the liquid pump assembly. The controller is configured to acquire the ambient temperature outputted from the temperature detection module, and when the ambient temperature is greater than a first temperature threshold, control the second motor to start.

The present application has the following benefits: after determining that an oil passage is in the jammed state, the controller may control the motor to turn on and off at a certain frequency so that the liquid pump releases the liquid for lubricating or cooling the chain at a lower frequency. Alternatively, the controller may reduce working power of the motor to reduce an amount of the liquid released by the liquid pump at a time to lubricate or cool the chain. As the working frequency or the working power of the liquid pump is reduced, an amount of the liquid outputted from the liquid pump becomes smaller and the jammed state of the oil passage is gradually relieved.

In this application, the terms "up", "down", "left", "right", "front", and "rear" " and other directional words are described based on the orientation or positional relationship shown in the drawings, and should not be understood as limitations to the examples of this application. In addition, in this context, it also needs to be understood that when it is mentioned that an element is connected "above" or "under" another element, it can not only be directly connected "above" or "under" the other element, but can also be indirectly connected "above" or "under" the other element through an intermediate element. It should also be understood that orientation words such as upper side, lower side, left side, right side, front side, and rear side do not only represent perfect orientations, but can also be understood as lateral orientations. For example, lower side may include directly below, bottom left, bottom right, front bottom, and rear bottom.

In this application, the terms "controller", "processor", "central processor", "CPU" and "MCU" are interchangeable. Where a unit "controller", "processor", "central processing", "CPU", or "MCU" is used to perform a specific function, the specific function may be implemented by a single aforementioned unit or a plurality of the aforementioned unit.

In this application, the term "device", "module" or "unit" may be implemented in the form of hardware or software to achieve specific functions.

In this application, the terms "computing", "judging", "controlling", "determining", "recognizing" and the like refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

As shown in <FIG>, the present application provides a chainsaw <NUM> including a chain <NUM>, a first motor <NUM>, a housing <NUM>, and a liquid pump assembly <NUM>. The chain <NUM> is used for implementing a cutting operation. The first motor <NUM> is used for driving the chain <NUM> to operate, and the first motor <NUM>, as a driver, has the advantages of a small volume, ease to install, and the like. The housing <NUM> is formed with a grip <NUM> for a user to hold, and the user may operate the chainsaw <NUM> by holding the grip <NUM>. A mounting cavity is formed in the housing <NUM>, and part of the mounting cavity extends into the grip <NUM>. The liquid pump assembly <NUM> is used for cooling or lubricating the chain <NUM>.

Specifically, the liquid pump assembly <NUM> includes a liquid pump <NUM> for releasing a liquid to lubricate or cool the chain <NUM>. It is to be noted that the liquid here may be lubricating oil to lubricate the chain <NUM> and accordingly, an oil pump is selected as the liquid pump <NUM>; or the liquid here may be cooling water to cool the chain <NUM> and accordingly, a water pump is selected as the liquid pump <NUM>.

In some specific examples, the liquid pump <NUM> may be driven by the first motor <NUM>, that is, the first motor <NUM> is connected to both the chain <NUM> and the liquid pump <NUM> through transmission assemblies to simultaneously drive the chain <NUM> and the liquid pump <NUM>. Optionally, a gear mechanism, a sprocket mechanism, or the like may be selected as a transmission assembly as required.

Of course, in some parallel examples, the chainsaw <NUM> further includes a second motor <NUM>, a motor shaft of the second motor <NUM> is connected to the liquid pump <NUM>, and the second motor <NUM> is used for driving the liquid pump <NUM> to operate. Compared with the first motor <NUM> for simultaneously driving the chain <NUM> and the liquid pump <NUM>, the independent second motor <NUM> is additionally disposed as a piece for driving the liquid pump <NUM> so that not only can a transmission assembly with a complex structure be omitted, but also it is easier to dispose the second motor <NUM> in the mounting cavity of the housing <NUM> since the second motor <NUM> occupies a small space, facilitating the full use of the space in the housing <NUM> and the miniaturization of the chainsaw <NUM>.

As shown in <FIG>, the chainsaw <NUM> further includes a battery pack coupling portion <NUM> for coupling a battery pack. Optionally, the battery pack is detachably connected to the battery pack coupling portion <NUM> to be convenient to detach for replacement or charging. Of course, the battery pack can supply power to the first motor <NUM> in addition to the second motor <NUM>. In addition to the use of the battery pack as a power piece, the first motor <NUM> and the second motor <NUM> may be directly connected to external mains electricity through a power line, thereby achieving power supply.

Still referring to <FIG>, a circuit board <NUM> is disposed at the battery pack coupling portion <NUM>, where the circuit board <NUM> is used for controlling the second motor <NUM>, for example, controlling a rotational speed of the second motor <NUM>. Specifically, an insertion cavity is formed in the battery pack coupling portion <NUM>, and the circuit board <NUM> is inserted into the insertion cavity.

Of course, the circuit board <NUM> may also be used for controlling the first motor <NUM>, for example, controlling a rotational speed of the first motor <NUM>. One circuit board <NUM> is used for controlling both the first motor <NUM> and the second motor <NUM> so that one circuit board <NUM> can be omitted, reducing a cost and an occupied space in the housing <NUM>.

In some examples, as shown in <FIG>, the second motor <NUM> is disposed within the grip <NUM>. The second motor <NUM> is disposed in a mounting cavity corresponding to the grip <NUM> so that a more reasonable layout can be achieved, not only can the mounting cavity corresponding to the grip <NUM> be utilized but also the weight of the chainsaw <NUM> can be more balanced, and the user uses the chainsaw with less labor.

Optionally, still referring to <FIG>, the liquid pump <NUM> is disposed within the grip <NUM>, that is, the liquid pump <NUM> is disposed in the mounting cavity corresponding to the grip <NUM>. Both the liquid pump <NUM> and the second motor <NUM> are disposed in the mounting cavity corresponding to the grip <NUM>, thereby facilitating a direct connection between the second motor <NUM> and the liquid pump <NUM> and avoiding a need to dispose a transmission structure for power transmission between the second motor <NUM> and the liquid pump <NUM>.

Along an operation direction of the chainsaw <NUM>, the liquid pump <NUM> and the second motor <NUM> are arranged front and back. In this manner, the space of the mounting cavity in the grip <NUM> can be fully utilized, and the liquid pump <NUM> and the second motor <NUM> are easy to assemble. Furthermore, along the operation direction of the chainsaw <NUM>, the liquid pump <NUM> is disposed on the front side of the second motor <NUM>. Furthermore, the liquid pump <NUM> and the second motor <NUM> both extend along a preset direction at a preset angle relative to a horizontal direction. It is to be noted that the preset angle here may be an acute angle, an obtuse angle, or a right angle. Of course, the liquid pump <NUM> and the second motor <NUM> may both extend along a vertical direction or along the horizontal direction.

As shown in <FIG>, the liquid pump assembly <NUM> further includes an oil can <NUM> and an oil passage, where the oil passage includes a first oil passage <NUM> and a second oil passage <NUM>. The liquid pump <NUM> has a first liquid port and a second liquid port, where the first liquid port communicates with an end of the first oil passage <NUM>, and the other end of the first oil passage <NUM> is disposed within a reservoir formed by the chain <NUM>. The second liquid port communicates with the oil can <NUM> via the second oil passage <NUM>. Driven by the liquid pump <NUM>, the lubricating oil or the cooling water stored in the oil can <NUM> can enter the liquid pump <NUM> through the second oil passage <NUM> and enter the reservoir at the chain <NUM> through the first oil passage <NUM>. When the chain <NUM> works, the liquid in the reservoir can lubricate or cool the chain <NUM>.

In some examples, the oil can <NUM> is disposed within the grip <NUM>, that is, the oil can <NUM> is disposed in the mounting cavity corresponding to the grip <NUM>. The oil can <NUM> is disposed in the mounting cavity corresponding to the grip <NUM> so that not only can the mounting cavity corresponding to the grip <NUM> be utilized and the weight of the chainsaw <NUM> be more balanced, but also the oil can <NUM> can be closer to the liquid pump <NUM> disposed within the grip <NUM> and the required length of the second oil passage <NUM> can be effectively reduced. Further, the oil can <NUM> is integrated on an inner wall surface of the housing <NUM> so that the oil can <NUM> can be formed while the housing <NUM> is manufactured, thereby avoiding the phenomenon of an accidental detachment of the oil can <NUM>.

As shown in <FIG>, in some examples, the chainsaw <NUM> may also include a temperature detection module <NUM>, a controller <NUM>, a speed detection module <NUM>, a memory <NUM>, a parameter reading module <NUM>, and a circuit detection module <NUM>.

The temperature detection module <NUM> may be used for detecting an ambient temperature, the temperature of the first motor <NUM>, the temperature of the second motor <NUM>, or the temperature of the circuit board <NUM>. Specifically, a temperature sensor may be disposed on the inner wall surface of the housing <NUM> to detect the ambient temperature in the mounting cavity, a temperature sensor may be disposed on a surface or in the vicinity of the first motor <NUM> to detect the temperature of the first motor <NUM>, a temperature sensor may be disposed on a surface or in the vicinity of the second motor <NUM> to detect the temperature of the second motor <NUM>, or a temperature sensor may be disposed on a surface or in the vicinity of the circuit board <NUM> to detect the temperature of the circuit board <NUM>. Optionally, the temperature detection module <NUM> may acquire the ambient temperature detected by the temperature sensor disposed on an inner wall of the mounting cavity of the housing <NUM> and use the ambient temperature in the mounting cavity of the housing <NUM> as the temperature of the chainsaw <NUM>.

The controller <NUM> may be one separate single-chip microcomputer or may be composed of multiple distributed single-chip microcomputers. The single-chip microcomputer can run control programs to control the first motor <NUM>, the second motor <NUM>, and other functional modules on the circuit board <NUM> to implement their functions.

The speed detection module <NUM> may be used for detecting the rotational speed of the first motor <NUM> and the rotational speed of the second motor <NUM>.

The circuit detection module <NUM> may be used for detecting an electrical parameter of a control circuit, where the electrical parameter may be a voltage value or a current value, and a variation of the voltage value or a variation of the current value within a preset duration may be calculated according to the voltage value or the current value. Specifically, a voltage value or a current value of the first motor <NUM> or the second motor <NUM> may be detected.

The memory <NUM> may be used for storing a preset parameter of the chainsaw <NUM>. For example, data such as an empirical parameter and a gear ratio of the transmission assembly are pre-stored in the memory <NUM>. The memory <NUM> may also be used for storing parameters detected by the temperature detection module <NUM>, the speed detection module <NUM>, and the circuit detection module <NUM>.

The parameter reading module <NUM> may be used for reading data stored in the memory <NUM>.

In some examples, the first motor <NUM> may simultaneously drive the chain <NUM> and the liquid pump <NUM>. In this example, the first motor <NUM> has a relatively high load capacity and is generally not damaged due to too large a load when directly started at a conventional low temperature. In some examples, the first motor <NUM> drives the chain <NUM>, the second motor <NUM> drives the liquid pump <NUM>, and the second motor <NUM> has a lower load capacity than the first motor <NUM>. In this example, the second motor <NUM> may be damaged due to too large a load when directly started at a low temperature. The present application provides an example that can prevent the second motor from being damaged due to too large a load when started at a low temperature.

The controller <NUM> is electrically connected to the first motor <NUM> and the liquid pump assembly <NUM>. Specifically, the controller <NUM> is electrically connected to the first motor <NUM>, the second motor <NUM>, and the temperature detection module <NUM>. The controller is configured to be capable of controlling the first motor <NUM> to start and stop, controlling the second motor <NUM> to start and stop, and acquiring an ambient temperature T0 detected by the temperature detection module <NUM>.

The controller <NUM> is electrically connected to the temperature detection module <NUM> to acquire the ambient temperature T0. The ambient temperature T0 may be the ambient temperature in the mounting cavity of the housing <NUM> and detected by the temperature detection module <NUM>. When the ambient temperature T0 is greater than a first temperature threshold T1, the controller <NUM> controls the second motor <NUM> to start.

When the working environment of the chainsaw <NUM> has a relatively low temperature, if the second motor <NUM> is directly started, the second motor <NUM> has too large a current and an increase in load. In this example, it is set that the second motor <NUM> is allowed to start only when it is greater than the first temperature threshold T1 so that the problem that the motor is damaged due to too large a load when directly started at a low temperature can be avoided.

If the first temperature threshold T1 is too low, a relatively large current is generated when the second motor <NUM> is started. If the first temperature threshold T1 is too high, an operator waits for a relatively long time, affecting working efficiency. Considering common working scenarios of the chainsaw <NUM>, it may be set that the first temperature threshold T1 is greater than or equal to -<NUM> and less than or equal to -<NUM>, so as to balance the preceding conflicting requirements.

In some low-temperature environments, after the chainsaw <NUM> is used for operation for a period of time, the operator turns off the chainsaw <NUM> for a short time, during which heat in the mounting cavity of the housing <NUM> is continuously lost and the temperature continuously decreases. When the operator restarts the chainsaw <NUM>, if the ambient temperature T0 is lower than the first temperature threshold T1, the second motor <NUM> cannot be started immediately, and the operator needs to wait for a period of time before continuing to use the chainsaw <NUM>, affecting the working continuity of the operator.

The controller <NUM> acquires a length of time L0 from when the first motor <NUM> is turned off to when the first motor <NUM> is restarted to obtain the length of time L0 from when the chainsaw <NUM> is turned off to when the chainsaw <NUM> is restarted. If the length of time L0 is greater than a preset waiting duration L1, the controller <NUM> determines that the chainsaw <NUM> is not restarted by the operator in a short time and controls the chainsaw <NUM> through steps S110 and S120. If the length of time L0 is less than or equal to the preset waiting duration L1, the controller <NUM> determines that the chainsaw <NUM> is restarted by the operator in a short time. At this time, a second temperature threshold T2 for the controller <NUM> to control the second motor <NUM> to restart should be lower than the first temperature threshold T1.

To provide better user experience, in some examples, the controller <NUM> may also acquire the length of time L0 from when the first motor <NUM> is turned off to when the first motor <NUM> is restarted. If the length of time L0 is less than or equal to the preset waiting duration L1 and the ambient temperature T0 is greater than the second temperature threshold T2, the controller <NUM> controls the second motor <NUM> to start. The second temperature threshold T2 is lower than the first temperature threshold T1.

When the chainsaw <NUM> is frequently started by the operator within a short time, a temperature threshold for the controller <NUM> to restart the second motor <NUM> is lower than a temperature threshold for the second motor <NUM> to start for the first time, thereby reducing the temperature threshold for the second motor <NUM> to start and satisfying the requirement of the operator for working continuity.

If the second temperature threshold T2 is too low, a relatively large current is also generated when the second motor <NUM> is started. If the second temperature threshold T2 is too high, the operator waits for a relatively long time, affecting the working efficiency. Considering common working scenarios of the chainsaw <NUM>, it may be set that a temperature difference between the second temperature threshold T2 and the first temperature threshold T1 is <NUM> to <NUM>. Specifically, the first temperature threshold T1 may be -<NUM> and the second temperature threshold T2 may be -<NUM>.

In some examples, the first motor <NUM> is used for driving the chain <NUM> to operate, and the second motor <NUM> is used for driving the liquid pump <NUM> to release the liquid for lubricating or cooling the chain <NUM>. When the ambient temperature T0 is less than the first temperature threshold T1, the controller <NUM> may control the first motor <NUM> to start to drive the chain <NUM> to operate. Since the first motor <NUM> continuously generates heat during operation, the heat continuously accumulates in the mounting cavity of the housing <NUM> so that the temperature in the mounting cavity of the housing <NUM> increases and then the temperature of the second motor <NUM> increases. When the ambient temperature T0 detected by the temperature detection module <NUM> is greater than the first temperature threshold T1, the controller <NUM> may control the second motor <NUM> to start. Thus, the second motor <NUM> is heated by the heat generated when the first motor <NUM> is working, thereby avoiding the problem of too large a load when the second motor <NUM> is directly started at a low temperature.

In some examples, mounting positions of the first motor <NUM> and the second motor <NUM> may be specially set such that an air path formed after the first motor <NUM> is started passes through the second motor <NUM>, thereby increasing a temperature rise speed of the second motor <NUM> and reducing a waiting time of the operator. Optionally, the first motor <NUM> may be configured to perform convective heat transfer with the second motor <NUM>, thereby increasing the temperature rise speed of the second motor <NUM>. Optionally, the first motor <NUM> may be positioned near the second motor <NUM> so that the heat of the first motor <NUM> is transferred to the second motor <NUM>. Optionally, the distance between the first motor <NUM> and the second motor <NUM> may be greater than or equal to <NUM> and less than or equal to <NUM>. Specifically, the axial distance between the first motor <NUM> and the second motor <NUM> may be greater than or equal to <NUM> and less than or equal to <NUM>. Specifically, the axial distance between the first motor <NUM> and the second motor <NUM> may be <NUM>. The preceding distance between the first motor <NUM> and the second motor <NUM> is set so that in a low-temperature environment, the heat of the first motor <NUM> can be rapidly transferred to the second motor <NUM>, thereby satisfying the requirement of the operator for rapidly starting the oil pump.

In some examples, when the ambient temperature in the mounting cavity of the housing <NUM> and detected by the temperature detection module <NUM> is used as the temperature of the second motor <NUM>, the temperature may not be accurate enough. Thus, the temperature detection module <NUM> may directly detect the temperature of the second motor <NUM> to achieve an accurate measured value. However, the surface of the second motor <NUM> is generally smooth and difficult for the temperature sensor to be mounted. The circuit board <NUM> is positioned relatively near the second motor <NUM> and has a relatively small temperature difference, and a suitable space for mounting the temperature sensor exists on the surface of the circuit board <NUM>. Therefore, the temperature of the circuit board <NUM> may be detected by the temperature detection module <NUM> as the temperature of the second motor <NUM>.

Since the circuit board <NUM> also generates heat in a working process, in some examples, the circuit board <NUM> may be configured to be capable of transferring heat to the second motor <NUM>, thereby increasing the temperature rise speed of the second motor <NUM> and reducing the waiting time of the operator. Optionally, the circuit board <NUM> may be configured to transfer heat to the second motor <NUM> through a wire for an electrical connection, where the wire can transfer an electrical signal and transfer the heat of the circuit board <NUM> to the second motor <NUM>.

As shown in <FIG>, the present application further provides a control method for starting the second motor <NUM> of the chainsaw <NUM>, and the control method includes the steps below.

In S110, the ambient temperature T0 outputted from the temperature detection module <NUM> is acquired.

In S120, the length of time L0 from when the first motor <NUM> is turned off to when the first motor <NUM> is restarted is acquired.

In S130, it is determined whether the length of time L0 is greater than the preset waiting duration L1. If L0 > L1, the controller <NUM> determines that the chainsaw is started for the first time and performs step S140. If L0 ≤ L1, the controller <NUM> determines that the chainsaw <NUM> is restarted in a short time and performs step S150.

In S140, it is determined whether the ambient temperature T0 is greater than the first temperature threshold T1. If T0 > T1, the second motor <NUM> is controlled to start. If T0 ≤ T1, the second motor <NUM> is controlled to be in an off state.

In S150, it is determined whether the ambient temperature T0 is greater than the second temperature threshold T2. If T0 > T2, the second motor <NUM> is controlled to start. If T0 ≤ T2, the second motor <NUM> is controlled to be in the off state. The second temperature threshold T2 is lower than the first temperature threshold T1.

The preceding parameters such as the preset waiting duration L1, the first temperature threshold T1, and the second temperature threshold T2 may be pre-stored in the memory <NUM> and read by the parameter reading module <NUM>.

In some working environments, the oil passage of the chainsaw <NUM> may be jammed. If the jammed state cannot be identified in time and released by some measures, the chainsaw <NUM> may be damaged. The present application provides an example that can solve the problem of the identification and release of a jam of the oil passage.

When the oil passage is jammed, the motor for driving the liquid pump <NUM> to release the liquid for lubricating or cooling the chain <NUM> changes in voltage and current. Therefore, a variation or a change rate of an electrical parameter of the motor within a preset detection duration L2 may be monitored so as to determine whether the oil passage of the liquid pump <NUM> is jammed.

In some specific examples, the first motor <NUM> may simultaneously drive the chain <NUM> and the liquid pump <NUM> to operate. Therefore, whether the oil passage of the liquid pump <NUM> is jammed may be determined through a variation or a change rate of an electrical parameter of the first motor <NUM> within the preset detection duration L2.

In some examples, the controller <NUM> of the chainsaw <NUM> is configured to be capable of acquiring the variation or the change rate of the electrical parameter of the motor within the preset detection duration L2. When the variation of the electrical parameter of the motor is greater than or equal to a preset variation threshold of the electrical parameter or when the change rate of the electrical parameter of the motor is greater than or equal to a preset change rate threshold of the electrical parameter, the controller <NUM> determines that the liquid pump is in the jammed state.

However, since the first motor <NUM> simultaneously drives the chain <NUM> and the liquid pump <NUM> to operate, a change of the electrical parameter due to a stutter of the chain <NUM> in the case where part of the chain <NUM> stutters may be falsely determined to be caused by the jam of the oil passage. In some examples, the motor may include the first motor <NUM> and the second motor <NUM>, the first motor <NUM> is used for driving the chain <NUM> to operate, and the second motor <NUM> is used for driving the liquid pump <NUM> to operate. Whether the oil passage of the liquid pump <NUM> is jammed may be determined through a variation or a change rate of an electrical parameter of the second motor <NUM> within the preset detection duration L2, thereby avoiding the false determination caused by the stutter of the chain <NUM>.

As described above, the variation or the change rate of the electrical parameter of the first motor <NUM> for simultaneously driving the chain <NUM> and the liquid pump <NUM> to operate is detected in some examples, or the variation or the change rate of the electrical parameter of the second motor <NUM> for driving the liquid pump <NUM> to operate is detected in some examples so that whether the oil passage is jammed can be determined. Thus, in a description concerning example in this example, when the "motor" is used, the "motor" may represent the first motor <NUM> for simultaneously driving the chain <NUM> and the liquid pump <NUM> to operate in some examples or represent the second motor <NUM> for driving the liquid pump <NUM> to operate in some examples. When the "second motor" is used, the "second motor" represents the second motor <NUM> for driving the liquid pump <NUM> to operate in some examples.

Too long a preset detection duration L2 affects whether the controller <NUM> can determine in time that the oil passage is jammed. Too short a preset detection duration L2 puts a relatively high performance requirement on the controller <NUM>, increasing a cost of the chainsaw <NUM>. After multiple experiments of the applicant, it is set that the preset detection duration L2 satisfies that <NUM> ≤ L2 ≤ <NUM>, which can satisfy the requirements under common working conditions and achieve a better balance between performance and cost.

Optionally, the electrical parameter may be the voltage value U or the current value I of the motor. Relatively mature techniques for measuring the voltage value U or the current value I exist in the existing market, and relevant instruments and devices are supplied sufficiently and cheaply. The voltage value U or the current value I of the motor is measured so that the electrical parameter of the motor can be accurately measured and the cost of the chainsaw <NUM> can be reduced.

When the variation of an electrical parameter of one or more electrical parameters detected by the circuit detection module <NUM> is greater than or equal to the preset variation threshold corresponding to the electrical parameter, or the change rate of an electrical parameter of the one or more electrical parameters is greater than or equal to the preset change rate threshold of the electrical parameter, the controller <NUM> determines that the oil passage is in the jammed state.

In some examples, a current variation threshold △Ifix and a voltage variation threshold △Ufix of the motor and a current change rate threshold RIfix and a voltage change rate threshold RUfix of the motor for the jam of the oil passage may be preset.

In common working environments, it may be set that the current variation threshold △ Ifix ≥ <NUM> mA, the voltage variation threshold ΔUfix ≥ <NUM> V, the current change rate threshold RIfix ≥ <NUM> mA/ms, or the voltage change rate threshold RUfix ≥<NUM> V/ms, so as to satisfy most working conditions of the chainsaw <NUM>. When the chain <NUM> operates on materials of different types, different values of the electrical parameter may be preset to adapt to corresponding working conditions.

The variation or the change rate of the electrical parameter of the motor is monitored so that whether the oil passage of the liquid pump <NUM> is jammed is determined. Besides this, the present application further provides a method for determining whether the oil passage is jammed by monitoring the temperature of the chainsaw <NUM>: after the oil passage is jammed, a lubricant or a cooling liquid outputted from the liquid pump <NUM> cannot satisfy the requirement for lubricating or cooling the chain <NUM>, and thus the temperature of the chainsaw <NUM> increases. In some examples, it may be set that if a sharp increase of the temperature of the chain is monitored, it may be determined that the oil passage of the liquid pump <NUM> is jammed.

As described above, the "motor" may represent the first motor <NUM> for simultaneously driving the chain <NUM> and the liquid pump <NUM> to operate in some examples or represent the second motor <NUM> for driving the liquid pump <NUM> to operate in some examples.

The controller <NUM> of the chainsaw <NUM> may be configured to, when the liquid pump <NUM> is in the jammed state, control the motor to be in an on-off mode. When the value of the electrical parameter is within a preset range, the controller <NUM> controls the motor to exit the on-off mode, where in the on-off mode, the motor is in an on state and an off state alternately.

The controller <NUM> of the chainsaw <NUM> may also be configured to, when the liquid pump <NUM> is in the jammed state, control the value of the electrical parameter of the motor to be lower than a preset electrical parameter threshold. When the value of the electrical parameter is within the preset range, the controller <NUM> controls the motor to exit the on-off mode, where in the on-off mode, the motor is in the on state and the off state alternately.

After determining that the oil passage is in the jammed state, the controller <NUM> may control the liquid pump assembly <NUM> to enter a throttling mode in which a supplied amount of the liquid is reduced; and when the liquid pump <NUM> exits the jammed state, the controller <NUM> may control the liquid pump assembly <NUM> to exit the throttling mode.

The controller <NUM> may control the motor to turn on and off at a frequency F so that the liquid pump <NUM> releases the liquid for lubricating or cooling the chain <NUM> at a lower frequency. Alternatively, the controller <NUM> may keep the current I lower than or equal to a current threshold Ifix or keep the voltage U lower than or equal to a voltage threshold Ufix to reduce working power of the liquid pump <NUM> and reduce an amount of the liquid released by the liquid pump <NUM> at a time to lubricate or cool the chain <NUM>. As the working frequency or the working power of the liquid pump <NUM> is reduced, an amount of the liquid outputted from the liquid pump <NUM> becomes smaller and the jammed state of the oil passage is gradually relieved.

Optionally, in some examples, after determining that the oil passage is in the jammed state, the controller <NUM> may not only control the motor to be in the on-off mode but also control the value of the electrical parameter of the motor to be lower than the preset electrical parameter threshold, thereby reducing the frequency at which the liquid pump <NUM> releases the lubricating or cooling liquid and reducing an amount of the lubricating or cooling liquid released by the liquid pump <NUM> at a time.

In some specific examples, the first motor <NUM> may simultaneously drive the chain <NUM> and the liquid pump <NUM> to operate. Therefore, the first motor <NUM> may be controlled to be in the on-off mode and/or the first motor <NUM> may be controlled to be in a low-power state so that the oil passage is gradually released from the jam.

However, since the first motor <NUM> simultaneously drives the chain <NUM> and the liquid pump <NUM> to operate, a decrease of a working frequency or working power of the first motor <NUM> may affect the cutting operation of the chain <NUM>. In some examples, the motor may include the first motor <NUM> and the second motor <NUM>, the first motor <NUM> is used for driving the chain <NUM> to operate, and the second motor <NUM> is used for driving the liquid pump <NUM> to operate. A working frequency or working power of the second motor <NUM> may be reduced so that the oil passage of the liquid pump <NUM> is gradually released from the jam, thereby avoiding an effect on the operation of the chain <NUM>.

In some examples, a range of values of the electrical parameter of the motor when the oil passage is not in the jammed state may be preset. Optionally, it may be set that when the value of the electrical parameter is N times the preset electrical parameter threshold, the value of the electrical parameter is within the preset range. In some examples, a voltage threshold Ufix and a current threshold Ifix of the motor when the oil passage is not in the jammed state may be preset. When the current I of the motor approximates to the current threshold Ifix or the voltage U approximates to the voltage threshold Ufix, the controller <NUM> may determine that the current oil passage is released from the jammed state or is about to be released from the jammed state and control the motor to exit the on-off mode to restore an amount of the liquid supplied by the liquid pump <NUM> to lubricate or cool the chain <NUM>.

In the common working environments, it may be set that <NUM> ≤ N ≤ <NUM>, so as to satisfy most working conditions of the chainsaw <NUM>. Specifically, under some working conditions where the chainsaw <NUM> has a strict requirement for lubrication or cooling, it may be set that <NUM> ≤ N ≤ <NUM> or <NUM> ≤ N ≤ <NUM>, so as to satisfy the strict requirement of the chainsaw <NUM> for lubrication or cooling.

In some examples, the controller <NUM> may control the motor to be in the on state within an on duration L3. Optionally, in the common working environments, it may be set that the on duration L3 is a fixed value, where <NUM> ≤ L3 ≤ <NUM>, so as to satisfy most working conditions of the chainsaw <NUM>. Alternatively, it may be set that the on duration L3 satisfies a linear relationship with △Ifix or △Ufix to adapt to lubrication or cooling requirements under different working conditions. In an example, the on duration L3 is negatively correlated to the current variation threshold △Ifix. That is to say, the larger the current variation threshold △Ifix, the smaller the on duration L set by the controller <NUM>, and vice versa. For example, L3 = K1 * △Ifix + b1, where K1 and b1 are constants and have different values under different working conditions. In an example, the on duration L3 is negatively correlated to the voltage variation threshold △Ufix. That is to say, the larger the voltage variation threshold △Ufix, the smaller the on duration L set by the controller <NUM>, and vice versa. For example, L3 = K2 * ΔUfix + b2, where K2 and b2 are constants and have different values under different working conditions.

In some examples, the controller <NUM> may control the motor to switch between the on state and the off state at the frequency F. Optionally, in the common working environments, it may be set that the on-off frequency F is a fixed value, where F ≤ <NUM>, so as to satisfy most working conditions of the chainsaw <NUM>. Alternatively, it may be set that the on-off frequency F satisfies a linear relationship with △Ifix or ΔUfix to adapt to the lubrication or cooling requirements under different working conditions. In an example, the on-off frequency F is positively correlated to the current variation threshold △Ifix. That is to say, the larger the current variation threshold △Ifix, the larger the on-off frequency F set by the controller <NUM>, and vice versa. For example, F = K3 * △Ifix + b3, where K3 and b3 are constants and have different values under different working conditions. In an example, the on-off frequency F is positively correlated to the voltage variation threshold △Ufix. That is to say, the larger the voltage variation threshold △Ufix, the larger the on-off frequency F set by the controller <NUM>, and vice versa. For example, F = K4 * ΔUfix + b4, where K4 and b4 are constants and have different values under different working conditions.

As shown in <FIG>, the present application provides a chainsaw with a controller for determining whether the liquid pump <NUM> of the chainsaw <NUM> is in the jammed state.

In S210, the variation or the change rate of the electrical parameter of the motor within the preset detection duration L2 is acquired.

In S220, when the variation of the electrical parameter of the motor is greater than or equal to the preset variation threshold of the electrical parameter or when the change rate of the electrical parameter of the motor is greater than or equal to the preset change rate threshold of the electrical parameter, it is determined that the liquid pump is in the jammed state.

As shown in <FIG>, the present application provides a chainsaw with a controller for releasing the jammed state of a liquid pump.

In S310, it is determined whether the liquid pump <NUM> is in the jammed state. If so, enter S320, and the liquid pump is controlled to enter a throttling mode in which a supplied amount of the liquid is reduced. If not, enter S340, and the liquid pump is controlled to supply the lubricant or cooling liquid to the chain normally.

After S320 and in S330, it is determined whether the liquid pump <NUM> exit the jammed state. If so, enter S340, and the liquid pump is controlled to supply the lubricant or cooling liquid to the chain normally. If not, return to S320.

In S410, it is determined whether the liquid pump <NUM> is in the jammed state. If so, the value of the electrical parameter of the second motor is controlled to be lower than the preset electrical parameter threshold so that the second motor is in the low-power mode, or the second motor is controlled in an on-off mode, and step S420 is performed. If not, the motor is controlled to exit the low-power mode or the on-off mode. In the on-off mode, the motor is in the on state and the off state alternately.

In S430, it is determined whether the value of the electrical parameter is within the preset range. If so, the motor is controlled to exit the low-power mode or the on-off mode, and step S440 is performed. If not, the motor is controlled to be in the low-power mode or the on-off mode, and return to S320.

The preceding parameters may be pre-stored in the memory <NUM> and read by the parameter reading module <NUM>, for example, empirical parameters such as the preset detection duration L2, the on duration L3, the on-off frequency F, the current variation threshold △Ifix, the voltage variation threshold △Ufix, the voltage value Ufix and the current value Ifix of the second motor <NUM> when the oil passage is not in the jammed state, N, K1, K2, K3, K4, b1, b2, b3, and b4.

In some examples, after the chainsaw <NUM> is activated, the liquid pump <NUM> continuously releases the liquid for lubricating or cooling the chain <NUM> until the chainsaw <NUM> is turned off. However, an output tool does not need to be lubricated or cooled all the time during the activation of the chainsaw <NUM>, and the continuous release causes a waste of the lubricating or cooling liquid. The present application provides an example that can reduce the consumption of the lubricating or cooling liquid while satisfying the good working performance of the chain <NUM>.

In some examples, the controller <NUM> of the chainsaw <NUM> is configured to control the second motor <NUM> to be on and off cyclically: the second motor <NUM> is controlled based on an active duration L4 to be on, and then the second motor <NUM> is controlled based on an inactive duration L5 to be off.

Since the second motor <NUM> is used for driving the liquid pump <NUM> to release the liquid for lubricating or cooling the chain <NUM>, the active duration L4 or the inactive duration L5 or the rotational speed V2 of the second motor <NUM> is controlled so that a volume or speed at which the liquid pump <NUM> releases the liquid can be controlled. Specifically, the controller <NUM> turns on and off the second motor <NUM> cyclically, thereby preventing the liquid pump <NUM> from continuously releasing the liquid for lubricating or cooling the chain <NUM>, reducing the consumption of the liquid, and preventing the oil passage from being jammed.

The longer the active duration L4, the better the lubrication and cooling effect on the chain <NUM>, but the consumption of the liquid also increases. The shorter the active duration L4, the smaller the consumption of the lubricating and cooling liquid, but the lubrication and cooling effect on the chain <NUM> becomes worse. The applicant has found through experiments that the active duration L4 set to be less than or equal to <NUM> and greater than or equal to <NUM> can balance the requirements of the chain <NUM> for working performance and saving the consumption of the liquid under the common working conditions.

The shorter the inactive duration L5, the better the lubrication and cooling effect on the chain <NUM>, but the consumption of the liquid also increases. The longer the inactive duration L5, the smaller the consumption of the lubricating and cooling liquid, but the lubrication and cooling effect on the chain <NUM> becomes worse. The applicant has found through experiments that the inactive duration L5 set to be greater than or equal to <NUM> and less than or equal to <NUM> can balance the requirements of the chain <NUM> for working performance and saving the consumption of the liquid under the common working conditions.

The applicant has found through experiments that the inactive duration L5 may be set to be longer than the active duration L4 so that the requirements of the chain <NUM> for working performance and saving the consumption of the liquid under the common working conditions can be balanced.

In some examples, the speed and a time for the liquid pump <NUM> to release the liquid for lubricating or cooling the chain <NUM> are fixed, which cannot satisfy the lubrication or cooling requirements of the chainsaw <NUM> under different working conditions. The present application provides an example that can adapt to the lubrication or cooling requirements of the chainsaw <NUM> under different working conditions.

In some examples, the chainsaw <NUM> further includes the temperature detection module <NUM> for detecting the ambient temperature T0 of the chainsaw <NUM>.

Optionally, the active duration L4 of the second motor <NUM> and the ambient temperature T0 of the chainsaw <NUM> may satisfy a linear or non-linear relationship so that different amounts of the lubricating or cooling liquid are released under different working conditions. In an example, the active duration L4 is negatively correlated to the ambient temperature T0. That is to say, the higher the ambient temperature T0, the shorter the active duration L4 of the second motor <NUM> set by the controller <NUM>, and vice versa. For example, L4 = K5 * T0 + b5, where K5 and b5 are constants and have different values under different working conditions.

Optionally, the inactive duration L5 of the second motor <NUM> and the ambient temperature T0 of the chainsaw <NUM> satisfy a linear or non-linear relationship so that different amounts of the lubricating or cooling liquid are released under different working conditions. In an example, the inactive duration L5 is positively correlated to the ambient temperature T0. That is to say, the higher the ambient temperature T0, the longer the inactive duration L5 of the second motor <NUM> set by the controller <NUM>, and vice versa. For example, L5 = K6 * T0 + b6, where K6 and b6 are constants and have different values under different working conditions.

In some examples, the chainsaw <NUM> further includes the speed detection module <NUM> for detecting the rotational speed V1 of the first motor <NUM>.

Optionally, the active duration L4 of the second motor <NUM> and the rotational speed V1 of the first motor <NUM> satisfy a linear or non-linear relationship so that different amounts of the lubricating or cooling liquid are released under different working conditions. In an example, the active duration L4 is positively correlated to the rotational speed V1 of the first motor <NUM>. That is to say, the higher the rotational speed V1 of the first motor <NUM>, the longer the active duration L4 of the second motor <NUM> set by the controller <NUM>, and vice versa. For example, L4 = K7 * V1 + b7, where K7 and b7 are constants and have different values under different working conditions.

Optionally, the inactive duration L5 of the second motor <NUM> and the rotational speed V1 of the first motor <NUM> satisfy a linear or non-linear relationship so that different amounts of the lubricating or cooling liquid are released under different working conditions. In an example, the inactive duration L5 is negatively correlated to the rotational speed V1 of the first motor <NUM>. That is to say, the higher the rotational speed V1 of the first motor <NUM>, the shorter the inactive duration L5 of the second motor <NUM> set by the controller <NUM>, and vice versa. For example, L5 = K8 * V1 + b8, where K8 and b8 are constants and have different values under different working conditions.

In some examples, the speed detection module <NUM> may also be used for detecting the rotational speed V2 of the second motor <NUM>, and the controller <NUM> is configured to be capable of controlling, according to the rotational speed V1 of the first motor <NUM>, the second motor <NUM> to rotate at the speed V2, where the rotational speed V1 of the first motor <NUM> and the rotational speed V2 of the second motor <NUM> satisfy a linear or non-linear relationship. In an example, the rotational speed V2 of the second motor <NUM> is positively correlated to the rotational speed V1 of the first motor <NUM>. That is to say, the higher the rotational speed V1 of the first motor <NUM>, the higher the rotational speed V2 of the second motor <NUM> set by the controller <NUM>, and vice versa. For example, V2 = K9 * V1 + b9, where K9 and b9 are constants and have different values under different working conditions.

In some examples, the rotational speed V2 of the second motor <NUM> is positively correlated to a linear speed V3 of the chain <NUM>. That is to say, the higher the linear speed V3 of the chain <NUM>, the higher the rotational speed V2 of the second motor <NUM> set by the controller <NUM>, and vice versa. In an example, an optimal amount of the lubricating or cooling liquid per unit length of the chain <NUM> is C0. For example, the rotational speed V2 of the second motor <NUM> satisfies that V2 = K0 * V3 * C0 + b0, where K0, C0, and b0 are constants and have different values under different working conditions. The linear speed V3 of the chain <NUM> is linearly and positively correlated to the rotational speed V1 of the first motor <NUM>. That is, the higher the rotational speed V1 of the first motor <NUM>, the higher the linear speed V3 of the chain <NUM>, and vice versa.

In some examples, the chainsaw <NUM> may be the chainsaw <NUM>, the chain <NUM> is the chain <NUM>, and the first motor <NUM> rotates the chain <NUM> by a sprocket. If a pitch of the chain <NUM> may be S0, the number of teeth of the sprocket may be N0, and a rotational speed of the sprocket may be V4, the linear speed of the chain <NUM> is <MAT> S<NUM>. The controller <NUM> may control the rotational speed V2 of the second motor <NUM> to satisfy that <MAT>, so as to consume a smaller amount of the liquid and obtain relatively high lubrication or cooling efficiency.

The preceding parameters may be pre-stored in the memory <NUM> and read by the parameter reading module <NUM>, for example, empirical parameters such as the optimal amount C0 of the lubricating or cooling liquid per unit length of the chain <NUM>, the pitch S0 of the chain <NUM>, the number N0 of teeth of the sprocket, K5, K6, K7, K8, K9, b5, b6, b7, b8, and b9.

Claim 1:
A chainsaw (<NUM>), comprising:
a chain (<NUM>) for implementing a cutting operation;
a liquid pump assembly (<NUM>) comprising a liquid pump (<NUM>) for lubricating or cooling the chain and a motor (<NUM>) for at least driving the liquid pump to operate; and
a controller (<NUM>) electrically connected to the liquid pump assembly;
characterized in that the controller is configured to:
when the liquid pump is in a jammed state, control the liquid pump assembly to enter a throttling mode in which a supplied amount of a liquid is reduced; and
when the liquid pump exits the jammed state, control the liquid pump assembly to exit the throttling mode.