Electric impact device and method for controlling the electric impact device

Abstract

The electric striking device (100) comprises a frame (101), an actuator member (103) that can move linearly relative to the frame, and a linear motor (104) having a movable element (105) that strikes the actuator member and a stator (106) with a winding that generates a magnetic force toward the movable element when current is supplied to the winding. The electric striking device includes a sensor system (107) that detects when the movable element passes a control limit position relative to the frame. The electric striking device includes a controller (108) configured to control the linear motor to reduce the magnetic force toward the movable element in response to a predetermined time having elapsed after the movable element has passed the control limit position as it moves toward the actuator member. Thus, when the movable element strikes the actuator member, unwanted current peaks can be avoided.

Description

Technical Field

[0001] The present disclosure relates to an electric impact device such as a hydraulic hammer device having a linear electric machine connectable to an excavator or another type of work machine. Further, the present disclosure relates to a method of controlling an electric impact device.

Background Art

[0002] Typically, an impact device is used as an accessory of an excavator or another work machine to crush, for example, stones, concrete, or some other materials. The impact device can be attached, for example, to the bottom of an excavator instead of a bucket. The impact device incorporates a mechanism configured to apply an impact to an actuator member, for example, a chisel, whose end forms a tip for transmitting the impact to the material to be crushed. At the same time as the actuator member is impacted, the impact device is pushed into the material to be crushed. Thus, due to the impact and the pushing, the above-mentioned tip penetrates into the material to be crushed, and as a result, the material is crushed.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The mechanism for applying an impact to the actuator member is typically hydraulic, but in recent years, electric mechanisms based on linear electric machines have also become more common because hydraulic mechanisms have problems. One of the problems faced by hydraulic impact devices is that they are prone to generating pressure shocks that can damage the hydraulic system of the work machine. These pressure shocks can be removed, although only to a certain extent, by an accumulator. Another problem with hydraulic impact devices is that they have relatively high power consumption. The hydraulic system includes a plurality of energy loss generating elements one after another in the direction of energy flow, reducing the efficiency of the entire system. For example, the energy loss generating elements include an engine driving a hydraulic pump, the hydraulic pump, and a piping and valve system that creates flow resistance. Heating the hydraulic oil of a hydraulic impact device can also cause problems in the hydraulic system of the work machine.

[0004] On the other hand, electric impact devices such as hammers or rock drills are not without their challenges. One challenge relates to the control of linear motors. For example, the forward and backward vibration of the movable part of a linear motor, which may occur after the movable part strikes an actuator member, such as a chisel, typically increases the time required between continuous impacts applied to the actuator member, thereby reducing the stroke frequency of the electric impact device. The stroke frequency is, for example, proportional to the efficiency of the electric impact device in crushing material. Furthermore, control methods commonly used in conjunction with hydraulic impact devices cannot be applied in conjunction with electric impact devices. [Means for solving the problem]

[0005] The following is a simplified overview to provide a basic understanding of several aspects of various embodiments of the invention. The overview is not a comprehensive overview of the invention. It is not intended to identify the main or important elements of the invention or to describe its scope. The following overview simply presents some concepts of the invention in a simplified form, serving as a prelude to a more detailed description of exemplary embodiments of the invention.

[0006] In this specification, the term "geometric," when used as a prefix, means a geometric concept that is not necessarily part of any physical object. For example, a geometric concept may be a geometric point, a geometric line or curve, a geometric plane, a geometric non-plane, a geometric space, or any other geometric entity in 0, 1, 2, or 3 dimensions.

[0007] According to the present invention, a new electric impact device is provided, such as an electric hammer device, an electric rock drill device, or an electric impact hammer for pile driving.

[0008] The electric striking device according to the present invention is A frame that can be attached to a work machine such as an excavator, the frame comprising an attachment member configured to be attached to the work machine such that the frame can be removed from the work machine non-destructively, An actuator member, such as a chisel, is supported so as to be able to move linearly with respect to the frame. A linear motor machine comprising a movable element configured to deliver an impact to an actuator member, and a stator mounted on a frame and having a winding configured to generate a magnetic force toward the movable element in response to an electric current supplied to the winding, A sensor system configured to detect when a movable element passes a control limit position relative to the frame, The system includes a controller configured to control the linear motor to reduce the magnetic force directed toward the movable element of the linear motor in response to a state in which a first predetermined time has elapsed after the movable element has passed a control limit position as it moves toward the actuator member in a first direction.

[0009] Depending on the control limit position, the first predetermined time may be 0, or it may be a time shorter than the time required for the movable element to move from the control limit position to the position where the movable element strikes the actuator member.

[0010] A linear motor may be controlled to reduce the magnetic force directed toward the mover, for example, by stopping the linear motor or by limiting the stator current of the linear motor. By controlling the linear motor to reduce the magnetic force before the mover strikes the actuator member, the speed of the mover can change rapidly, thereby avoiding unwanted transient peaks in the stator current. For example, in the case of a linear induction machine, a state in which the direction of movement of the mover changes rapidly corresponds to a short-circuit state from the stator's perspective, which can result in high transient peaks in the stator current. In another example, in the case of a permanent magnet machine, a state in which the direction of movement of the mover changes rapidly represents a strong asynchronous state in which high transient peaks in the stator current can result. Unwanted transient peaks in the stator current can stress the power electronics system supplying the linear motor and complicate the control of the linear motor. Therefore, it is advantageous to avoid or at least reduce the transient peaks of the types described above.

[0011] In an exemplary and non-limiting embodiment of an electric strike device, the controller is configured to actuate a linear motor to generate a magnetic force that moves the mover away from the actuator member in the second direction in response to the mover moving in a second direction and the mover passing a control limit position. Since the linear motor is controlled to generate a magnetic force that moves the mover away from the actuator member, i.e., in the second direction, the forward and backward vibration of the mover can be avoided or at least reduced after the mover bounces off the actuator member and passes the control limit position. Thus, the time required between continuous impacts applied to the actuator member can be reduced, thereby increasing the stroke frequency of the electric strike device.

[0012] In an exemplary and non-limiting embodiment of an electric striking device, the controller is further configured to actuate a linear motor to generate a magnetic force that moves the movable element away from the actuator member, i.e., in a second direction, in response to a second predetermined time having elapsed after the movable element has passed a control limit position as it moves toward the actuator member. The second predetermined time is longer than the first predetermined time described above. This time-based actuation is necessary, for example, when the actuator member is in contact with a material whose mechanical properties prevent the movable element from bouncing away from the actuator member, so that the movable element passes the control limit position as a result of rebound.

[0013] In an exemplary and non-limiting embodiment of an electric strike device, a sensor system is configured to detect when the movable element passes a safety limit position that is further than a control limit position in a first direction, and a controller is configured to prevent the linear motor from operating in response to the movable element passing the safety limit position as it moves toward the actuator member. Passing the safety limit position means that there is no material in contact with the actuator member, or the properties of the material in contact with the actuator member are not suitable for generating a sufficient counterforce against the actuator member, thus advantageously preventing the movable element from imparting more impact to the actuator member.

[0014] According to the present invention, A frame that can be attached to a work machine, the frame comprising an attachment member configured to be attached to the work machine such that the frame can be removed from the work machine non-destructively, An actuator member supported so as to be able to move linearly with respect to the frame, A linear motor machine comprising a movable element configured to deliver an impact to an actuator member, and a stator mounted on a frame and having a winding configured to generate a magnetic force toward the movable element in response to an electric current supplied to the winding, A novel method for controlling an electric striking device is also provided, which includes a sensor system configured to detect when a movable element passes a control limit position relative to the frame.

[0015] The method according to the present invention comprises the step of controlling a linear motor to reduce the magnetic force toward the movable element in response to a state in which a first predetermined time has elapsed after the movable element has passed a control limit position as it moves toward an actuator member in a first direction.

[0016] Exemplary and non-limiting embodiments are described in the attached dependent claims.

[0017] Various exemplary and non-limiting embodiments relating to the structure and operation methods, along with additional purposes and advantages, will be best understood from the following descriptions of specific exemplary and non-limiting embodiments when read in conjunction with the accompanying drawings.

[0018] The verbs "to include" and "to have" are used herein as open limitations that neither exclude nor require the presence of features not listed.

[0019] The features enumerated in the dependent claims may be freely combined with each other unless otherwise specified. Furthermore, throughout this specification, the use of "a" or "an," i.e., the singular form, is understood not to exclude the plural. [Brief explanation of the drawing]

[0020] Exemplary and non-exclusive embodiments and their advantages are described in more detail below with reference to the accompanying drawings, in an illustrative sense. [Figure 1a] Figure 1a illustrates an electric striking device according to exemplary and non-limiting embodiments. [Figure 1b] Figure 1b illustrates an electric striking device according to an exemplary and non-limiting embodiment. [Figure 1c] Figure 1c illustrates an electric striking device according to an exemplary and non-limiting embodiment. [Figure 1d] FIG. 1d illustrates an electric impact device according to exemplary and non-limiting embodiments. [Figure 2] FIG. 2 shows a flowchart of a method of controlling an electric impact device according to exemplary and non-limiting embodiments. DETAILED DESCRIPTION

[0021] The present invention and its embodiments are not limited to the exemplary and non-limiting embodiments described below. Thus, the specific examples provided in the following description should not be construed as limiting the scope and / or applicability of the appended claims. The lists and groups of examples provided in the following description are not exhaustive unless otherwise specified.

[0022] FIG. 1a shows an electric impact device 100 according to exemplary and non-limiting embodiments. FIGS. 1b and 1c show cross-sectional views taken along line A-A shown in FIG. 1a in two different states. The geometric cross-section is parallel to the yz plane of the coordinate system 199. FIG. 1d shows an enlarged view of part B of FIGS. 1b and 1c. The electric impact device 100 includes a frame 101 that can be attached to a work machine, such as the bottom of an excavator, instead of a bucket. The frame 101 includes an attachment member 102 for attaching the frame 101 to the work machine such that the frame 101 can be removably detached from the work machine without damage. The electric impact device 100 includes an actuator member 103, such as a chisel, that is supported to be linearly movable with respect to the frame 101. The end of the actuator member 103 is formed to constitute a tip for breaking materials, such as stone or concrete.

[0023] The electric strike device 100 comprises a linear motor 104 having a movable element 105 and a stator 106. The stator 106 is mounted on a frame 101 and has windings configured to generate a magnetic force toward the movable element 103 in response to a current supplied to the windings. The movable element 105 is configured to strike the actuator member 103 in a first direction, i.e., in the negative z direction of coordinate system 199. For example, the windings of the stator 106 may constitute a multiphase winding, such as a two-phase or three-phase winding. In the exemplary electric strike device 100 described in Figures 1a to 1d, the linear motor 104 is a tubular linear motor configured such that the conductor coils of the windings surround the movable element 105. Figures 1b, 1c, and 1d show cross-sectional views of the conductor coils of the windings. In Figures 1b and 1c, the cross-section of the conductor coils is shown by a black rectangular pattern. In Figure 1d, two of the winding conductor coils are represented by reference numerals 119 and 120. For example, the movable element 105 may be substantially rotationally symmetric with respect to the geometric line 128 shown in Figure 1d.

[0024] The electric striking device 100 includes a sensor system 107 configured to detect when the movable element 105 passes a control limit position relative to the frame 101. Figure 1b shows the state when the movable element 105 is in the control limit position relative to the frame 101. In the exemplary electric striking device 100 described in Figures 1a to 1d, the sensor system 107 includes a first induction sensor 111 configured to detect when the movable element 105 passes a control limit position. However, the sensor system 107 may also include several other sensors for detecting when the movable element 105 passes a control limit position, such as a capacitive sensor, an optical sensor, or a mechanical sensor. It should be noted that a reference point can be defined in different ways on the movable element 105. For example, in Figure 1b, the reference point on the movable element 105 is the upper end of the movable element, and the first induction sensor 111 detects when the upper end of the movable element passes the first induction sensor 111. However, different points on the movable element can also act as reference points. For example, the lower part of the movable element may have a recess, and a sensor located at the lower part of the stator may be configured to detect when the recess passes through the sensor.

[0025] The electric striking device 100 includes a controller 108 configured to control the linear motor 104 to reduce the magnetic force directed toward the movable element 105 in response to a state in which a first predetermined time has elapsed after the movable element 105 has passed the control limit position described above when it moves toward the actuator member 103 in a first direction, i.e., in the negative z direction of the coordinate system 199. Depending on the control limit position, the first predetermined time may be 0, or it may be a time shorter than the time required for the movable element 105 to move from the control limit position to the position where it strikes the actuator member 103. The linear motor 104 may be controlled to reduce the magnetic force directed toward the movable element 105, for example, by stopping the linear motor 104 or by limiting the stator current of the linear motor. Before the movable element 105 strikes the actuator member 103, the linear motor is controlled to reduce the magnetic force, thereby allowing the velocity of the movable element to change rapidly, thus avoiding unwanted transient peaks in the stator current.

[0026] In exemplary and non-limiting embodiments of the electric impact device, the controller 108 is configured to stop the linear motor 104 to reduce the magnetic force in response to the above-described state after a first predetermined time has elapsed, following the passage of the above-described control limit position when the movable element 105 moves toward the actuator member 103 in a first direction, i.e., when moving in the negative z direction of the coordinate system 199. In exemplary and non-limiting embodiments of the electric impact device, the controller 108 is configured to stop the linear motor 104 such that the controllable power electronics switch of the power inverter 109 of the linear motor 104 becomes unidirectionally conductive. In Figures 1b and 1c, one of the controllable power electronics switches of the power inverter 109 is represented by reference numeral 114. In the unidirectionally conductive state, each controllable power electronics switch conducts current only in the forward direction of the diode of the controllable power electronics switch. The diode may be a separate component connected antiparallel to the controllable element of the controllable power electronics switch, or the diode may be an integral component formed from the semiconductor material of the controllable element. For example, the controllable element may be an insulated-gate bipolar transistor (IGBT), a gate-off thyristor (GTO), or several other suitable elements that can be switched on and off. When the controllable power electronics switch of the power inverter 109 is in a unidirectional conducting state, the magnetic energy stored in the windings of the stator 106 is released through the diode of the controllable power electronics switch. Therefore, the induced current is not abruptly interrupted and no overvoltage occurs.

[0027] In an exemplary and non-limiting embodiment of the electric strike device, the controller 108 is configured to actuate a linear motor 104 to generate a magnetic force that moves the movable element 105 away from the actuator member in the second direction, i.e., in the positive z direction of the coordinate system 199, in response to the movable element 105 passing the control limit position as it moves in the second direction, i.e., in the positive z direction of the coordinate system 199. The linear motor 104 is controlled to generate a magnetic force that moves the movable element 105 away from the actuator member 103 after it has bounced off the actuator member 103 and passed the control limit position, so that longitudinal vibrations of the movable element 105 can be avoided or at least reduced. Thus, the time required between continuous impacts delivered to the actuator member 103 by the movable element 105 can be reduced, thereby increasing the stroke frequency of the electric strike device 100.

[0028] In an exemplary and non-limiting embodiment of an electric striking device, the controller 108 is further configured to actuate a linear motor 104 to generate a magnetic force that moves the movable element 105 away from the actuator member 103 in response to a second predetermined time having elapsed after the movable element 105 has passed the control limit position as it moves toward the actuator member 103. The second predetermined time is longer than the first predetermined time described above. This time-based actuation is necessary, for example, when the actuator member 103 is in contact with a material whose mechanical properties prevent the movable element 105 from bouncing away from the actuator member, so that the movable element 105 passes the control limit position as a result of rebound.

[0029] In exemplary and non-limiting embodiments of the electric strike device, the sensor system 107 is configured to detect when the movable element 105 passes a safety limit position that is further than the control limit position described above, in a first direction, i.e., in the negative z direction of coordinate system 199. Figure 1c shows the state in which the movable element 105 is in the safety limit position relative to the frame 101. In the exemplary electric strike device 100 described in Figures 1a to 1d, the sensor system 107 includes a second induction sensor 112 configured to detect when the movable element 105 passes the safety limit position. However, the sensor system 107 may also include several other sensors for detecting when the movable element 105 passes the safety limit position, such as capacitive sensors, optical sensors, or mechanical sensors. The controller 108 is configured to prevent the operation of the linear motor 104 in response to the state in which the movable element 105 passes the safety limit position as it moves toward the actuator member 103. Passing the safety limit position may mean that there is no material in contact with the tip of the actuator member 103, or that the properties of the material in contact with the tip of the actuator member are not suitable for generating sufficient counterforce against the actuator member 103. To avoid damage that may occur in the above-described conditions, the movable element 105 is advantageously prevented from applying more impact to the actuator member 103.

[0030] In exemplary and non-limiting embodiments of the electric strike machine, the sensor system 107 is configured to detect when the movable element 105 passes an upper limit position that is further than the control limit position in a second direction, i.e., in the positive z direction of the coordinate system 199. In the exemplary electric strike machine 100 described in Figures 1a to 1d, the sensor system 107 includes a third induction sensor 110 configured to detect when the movable element 105 passes an upper limit position. However, the sensor system 107 may also include several other sensors for detecting when the movable element 105 passes an upper limit position, such as a capacitive sensor, an optical sensor, or a mechanical sensor. The controller 108 is configured to stop the linear motor 104 in response to the movable element 105 passing an upper limit position when it moves away from the actuator member 103 in a second direction, i.e., when it moves in the positive z direction of the coordinate system 199. The controller 108 is configured to actuate the linear motor 104 to generate a magnetic force that moves the movable element 105 toward the actuator member 103 in the first direction, i.e., in the negative z direction of the coordinate system 199, in response to the movable element 105 passing the upper limit position as it moves in the first direction, i.e., in the negative z direction of the coordinate system 199. The movable element 105 may be returned from the tip position in the positive z direction of the coordinate system 199, for example, by gas pressure generated in space 113. Sensors 111 and / or sensor 112 may also be configured to detect the state in which the movable element 105 passes the upper limit position, in which case sensor 110 is not required. It should be noted that the motorized striking device in exemplary and non-limiting embodiments may have different devices for controlling the movement of the movable element 105 at and near the tip position in the positive z direction of the coordinate system 199.

[0031] Implementations of the controller 108 shown in Figures 1b and 1c may be based on one or more analog circuits, one or more digital processing circuits, or a combination thereof. Each digital processing circuit may be a programmable processor circuit with appropriate software, such as a dedicated hardware processor like an application-specific integrated circuit (ASIC), or a configurable hardware processor like a field-programmable gate array (FPGA). Furthermore, the controller 108 may include one or more memory circuits, each of which may be, for example, a random access memory (RAM) circuit.

[0032] In the exemplary electric striking device 100 described in Figures 1a to 1d, the movable element 105 comprises annular permanent magnets arranged continuously along the longitudinal direction of the movable element 105, i.e., in the z-axis direction of the coordinate system 199. The axial direction of the annular shape of each permanent magnet coincides with the longitudinal direction of the movable element 105. In Figure 1d, two of the annular permanent magnets are denoted by reference numerals 121 and 122. The magnetization direction of the permanent magnets coincides with the longitudinal direction of the movable element 105, and the magnetization directions of the consecutive permanent magnets are opposite to each other. The magnetization direction of the permanent magnets is indicated by arrows in Figure 1d. Exemplary magnetic flux lines are shown by dashed lines. In this exemplary case, the movable element 105 comprises a center rod 125 and annular ferromagnetic elements provided around the center rod 125 to form a ferromagnetic core structure of the movable element 105. In Figure 1d, two of the annular ferromagnetic elements of the movable element 105 are denoted by reference numerals 126 and 127. As shown in Figure 1d, each annular permanent magnet is located between two consecutive annular ferromagnetic elements. Preferably, the center rod 125 of the movable element 105 is formed from a non-ferromagnetic material to maximize the magnetic coupling between the permanent magnet and the windings of the stator 106, i.e., to minimize leakage flux through the center rod 125.

[0033] In the exemplary electric striking device 100 described in Figures 1a to 1d, the ferromagnetic core structure 131 of the stator 106 comprises annular ferromagnetic elements surrounding the movable element 105 and stacked continuously in the longitudinal direction of the movable element 105, forming grooves for the conductor coils of the stator winding. In Figure 1d, two of the annular ferromagnetic elements of the stator 106 are represented by reference numerals 123 and 124. An exemplary method of winding the stator 106 is such that each groove has only one conductor coil belonging to one phase of the winding. For example, it is also possible to provide two conductor coils belonging to either the same phase of the winding or two different phases of the winding in each groove. The stator 106 also comprises a stator frame 129 having cooling channels for flowing a cooling fluid, such as water or air. In Figure 1d, one of the cooling channels is represented by reference numeral 130.

[0034] The electric striking devices in the exemplary and non-limiting embodiments may have different ferromagnetic core structures for the movable and / or different ferromagnetic core structures for the stator, and it should be noted that the electric striking devices in the exemplary and non-limiting embodiments are not limited to any particular ferromagnetic core structure for the movable and / or stator.

[0035] Furthermore, it should be noted that the electric striking devices according to embodiments of the present invention are not limited to any particular type of linear motor. For example, the linear motor of the electric striking device according to exemplary and non-limiting embodiments may be a flux-switching permanent magnet synchronous machine (FSPMSM) in which the permanent magnet is located in the stator. The electric striking devices according to exemplary and non-limiting embodiments may also comprise a reluctance linear motor or a linear induction machine that does not require permanent magnets. In a reluctance linear motor, all magnetic flux is generated by an electric current, and the magnetic force toward the mover is generated by fluctuations in reluctance based on the structure of the mover. Correspondingly, in a linear induction machine, all magnetic flux is generated by an electric current, and the magnetic force toward the mover is generated by an electric current induced in the mover.

[0036] Figure 2 shows, A frame that can be attached to a work machine, the frame comprising an attachment member configured to be attached to the work machine such that the frame can be removed from the work machine non-destructively, An actuator member supported so as to be able to move linearly with respect to the frame, A linear motor machine comprising a movable element configured to deliver an impact to an actuator member, and a stator mounted on a frame and having a winding configured to generate a magnetic force toward the movable element in response to an electric current supplied to the winding, A flowchart shows a method of controlling an electric striking device comprising a sensor system configured to detect when a movable element passes a control limit position relative to a frame, according to exemplary and non-limiting embodiments.

[0037] The method comprises the following steps: step 201, which controls the linear motor to reduce the magnetic force toward the movable element in response to a state in which a first predetermined time has elapsed after the movable element has passed a control limit position as it moves toward the actuator member in a first direction.

[0038] A method according to exemplary and non-limiting embodiments includes the step of acting a linear motor to generate a magnetic force that moves the movable in the second direction away from the actuator member in response to the movable moving in a second direction and the movable passing a control limit position.

[0039] A method according to exemplary and non-limiting embodiments includes the step of stopping the linear motor to reduce the magnetic force in response to a state in which a first predetermined time has elapsed after the movable element has passed a control limit position as it moves toward the actuator member in a first direction.

[0040] Methods according to exemplary and non-limiting embodiments include the step of setting a controllable power electronics switch of the power inverter of a linear motor into a unidirectional conductive state in order to stop the linear motor.

[0041] A method according to exemplary and non-limiting embodiments includes the step of acting a linear motor to generate a force that moves the movable element away from an actuator member in a second direction in response to a state in which the movable element has passed a control limit position as it moves in a first direction and a second predetermined time has elapsed, wherein the second predetermined time is longer than the first predetermined time.

[0042] In exemplary and non-limiting embodiments, the sensor system includes a first induction sensor configured to detect when a movable element passes a control limit position.

[0043] In exemplary and non-limiting embodiments of the method, the sensor system is configured to detect when the movable element passes a safety limit position that is further away from a control limit position in a first direction, and the method comprises the step of preventing the operation of a linear motor in response to the movable element passing a safety limit position in a first direction.

[0044] In exemplary and non-limiting embodiments, the sensor system includes a second induction sensor configured to detect when a movable element passes a safety limit position.

[0045] In exemplary and non-limiting embodiments, the linear motor is a tubular linear motor configured such that the conductor coils of the windings surround the movable element.

[0046] In exemplary and non-limiting embodiments of the method, the movable element comprises annular permanent magnets arranged continuously in the longitudinal direction of the movable element, wherein the axial direction of the annular shape of each annular permanent magnet coincides with the longitudinal direction of the movable element, and the magnetization direction of the annular permanent magnets coincides with the longitudinal direction of the movable element such that the magnetization directions of the consecutive annular permanent magnets are opposite to each other.

[0047] In exemplary and non-limiting embodiments, the stator ferromagnetic core structure comprises longitudinally continuous annular ferromagnetic elements surrounding the movable and forming grooves for the winding conductor coils.

[0048] In exemplary and non-limiting embodiments, the movable element comprises a center rod formed from a non-ferromagnetic material and an annular ferromagnetic element around the center rod that forms a ferromagnetic core structure of the movable element.

[0049] The present invention and its embodiments are not limited to the exemplary and non-limiting embodiments described above. Accordingly, the specific examples provided in the above description should not be construed as limiting the scope and / or applicability of the appended claims. The list and groups of examples provided in the above description are not exhaustive unless otherwise specified.

Claims

1. A frame (101) that can be attached to a work machine, wherein the frame comprises an attachment member (102) configured to be attached to the work machine such that the frame can be removed from the work machine non-destructively, An actuator member (103) is supported so as to be able to move linearly with respect to the frame (102), A linear motor machine (104) comprising: a movable element (105) configured to deliver an impact to the actuator member (103); and a stator (106) attached to the frame (102) and having a winding configured to generate a magnetic force toward the movable element (105) in response to a current supplied to the winding; A sensor system (107) configured to detect when the movable element passes a control limit position relative to the frame, An electric striking device (100) equipped with, The electric striking device is characterized by comprising a controller (108) configured to control the linear motor (104) to reduce the magnetic force directed toward the movable element (105) in response to a state in which a first predetermined time has elapsed after the movable element (105) has passed the control limit position as it moves toward the actuator member (103).

2. The electric striking device according to claim 1, wherein the controller (108) is configured to actuate the linear motor (104) to generate a magnetic force that moves the movable element (105) away from the actuator member in the second direction (+z) in response to the movable element (105) moving in the second direction and the movable element (105) passing the control limit position.

3. The electric striking device according to claim 1 or 2, wherein the controller (108) is configured to stop the linear motor (104) in order to reduce the magnetic force in response to a state in which a first predetermined time has elapsed after the movable element (105) has passed the control limit position when moving toward the actuator member (103) in the first direction (-z).

4. The electric striking device according to claim 3, wherein the controller (108) is configured to set a controllable power electronics switch of the power inverter of the linear motor to a unidirectional conductive state in order to stop the linear motor.

5. The electric striking device according to any one of claims 1 to 4, wherein the controller is configured to actuate the linear motor to generate the magnetic force that moves the movable element away from the actuator member in the second direction (+z) in response to a second predetermined time having elapsed after the movable element has passed the control limit position as it moves in the first direction, the second predetermined time being longer than the first predetermined time.

6. The electric striking device according to any one of claims 1 to 5, wherein the sensor system (107) comprises a first induction sensor (111) configured to detect when the movable element passes the control limit position.

7. The electric striking device according to any one of claims 1 to 6, wherein the sensor system (107) is configured to detect when the movable element passes a safety limit position that is further away from the control limit position in the first direction, and the controller is configured to prevent the operation of the linear motor in response to the state that the movable element has passed the safety limit position when moving in the first direction.

8. The electric striking device according to claim 7, wherein the sensor system comprises a second induction sensor (112) configured to detect when the movable element passes the safety limit position.

9. The electric striking device according to any one of claims 1 to 8, wherein the linear motor (104) is a tubular linear motor configured such that the winding conductor coils (119, 120) surround the movable element (105).

10. A frame (101) that can be attached to a work machine, wherein the frame comprises an attachment member (102) configured to be attached to the work machine such that the frame can be removed from the work machine non-destructively, An actuator member (103) is supported so as to be able to move linearly with respect to the frame, A linear motor machine (104) comprising a movable element (105) configured to deliver an impact to the actuator member, and a stator (106) attached to the frame and having a winding configured to generate a magnetic force toward the movable element in response to a current supplied to the winding, A sensor system (107) configured to detect when the movable element passes a control limit position relative to the frame, A method for controlling an electric striking device (100) equipped with the following: The method is characterized by comprising the step (201) of controlling the linear motor to reduce the magnetic force toward the movable element in response to a state in which a first predetermined time has elapsed after the movable element has passed the control limit position when moving toward the actuator member in a first direction (-z).

11. The method according to claim 10, further comprising the step of operating the linear motor to generate a magnetic force that moves the movable element away from the actuator member in the second direction (+z) in response to the movable element moving in a second direction and the movable element passing through the control limit position.

12. The method according to claim 10 or 11, further comprising the step of stopping the linear motor to reduce the magnetic force in response to a state in which a first predetermined time has elapsed after the movable element has passed the control limit position as it moves toward the actuator member in the first direction (-z).

13. The method according to claim 12, further comprising the step of setting a controllable power electronics switch of the power inverter of the linear motor into a unidirectional conductive state in order to stop the linear motor.

14. The method according to any one of claims 10 to 13, comprising the step of operating the linear motor to generate the force that moves the movable element away from the actuator member in the second direction (+z) in response to a state in which a second predetermined time has elapsed after the movable element has passed the control limit position as it moves in the first direction, wherein the second predetermined time is longer than the first predetermined time.

15. The method according to any one of claims 10 to 14, wherein the sensor system is configured to detect when the movable element passes a safety limit position that is further away from the control limit position in the first direction, and the method comprises the step of preventing the operation of the linear motor in response to the state that the movable element has passed the safety limit position as it moves in the first direction.

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