Electric lubricant dispenser, and method for dispensing lubricant from an electric lubricant dispenser.

Abstract

This invention provides a technology that can properly detect the presence of gas in the pump of an electric lubricant dispenser. [Solution] One aspect of the present disclosure provides an electric lubricant dispenser comprising a motor, a pump, a drive circuit, and a control circuit. The pump is driven by the motor and discharges lubricant. The drive circuit drives the motor. The control circuit controls the drive circuit to rotate the motor. The control circuit performs predetermined processing based on whether the actual operating amount satisfies predetermined requirements while the motor is being driven. The actual operating amount represents the actual rotational speed of the motor, or the magnitude of fluctuations in the actual rotational speed. The predetermined requirement indicates that gas is mixed into the pump.

Description

Technical Field

[0001] The present disclosure relates to an electric lubricant feeder.

Background Art

[0002] Patent Document 1 discloses a grease discharge device provided with a pump. In this grease discharge device, the pump receives grease from a tank and discharges the grease.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a grease discharge device, air may be mixed into the grease in the pump. When air is mixed into the pump, appropriate discharge of the grease by the pump may be inhibited by the air. For example, the discharge amount of the grease may temporarily decrease or the grease may temporarily stop being discharged.

[0005] One aspect of the present disclosure aims to provide a technique capable of appropriately detecting that gas is mixed into a pump.

Means for Solving the Problems

[0006] One aspect of the present disclosure provides an electric lubricant feeder including a motor, a pump, a drive circuit, and a control circuit. The pump is driven by the motor. The pump discharges a lubricant. The drive circuit drives the motor.

[0007] The control circuit controls the drive circuit so as to rotate the motor. The control circuit performs a predetermined process based on whether the actual operating amount meets a predetermined requirement while the motor is running. The actual operating amount represents the actual rotational speed of the motor, or the magnitude of the fluctuation in the actual rotational speed. The predetermined requirement indicates that gas is mixed into the pump. The predetermined requirement may also indicate that there is a possibility that gas is mixed into the pump. In other words, the fact that the actual operating amount meets the predetermined requirement may mean that gas is mixed into the pump (or there is a possibility that gas is mixed in).

[0008] An electric lubricant dispenser configured in this way can properly detect if gas is mixed into the pump. Another aspect of this disclosure is a method for dispensing lubricant from an electric lubricant dispenser, The pump of the electric lubricant dispenser, which is configured to dispense lubricant, is driven by the motor of the electric lubricant dispenser, During motor operation, the electric lubricant dispenser performs a predetermined process based on the fact that the actual operating amount, which indicates the actual rotational speed of the motor or the magnitude of fluctuations in the actual rotational speed, satisfies predetermined requirements indicating that gas is mixed into the pump. This provides a method for providing this.

[0009] This method allows for the proper detection of gas contamination in the pump of an electric lubricant dispenser. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the electric lubricant dispenser according to the first embodiment. [Figure 2] This is a central longitudinal cross-section of an electric lubricant dispenser. [Figure 3] This is an explanatory diagram illustrating how a plunger moves up and down due to the rotation of a motor. [Figure 4] This is a plan view of the control panel for an electric lubricant dispenser. [Figure 5] This is a circuit diagram showing the electrical configuration of an electric lubricant dispenser. [Figure 6]It is a functional block diagram of a control circuit in an electric lubricant feeder. [Figure 7] It is an explanatory diagram showing an operation example of a motor when the pump is in a normal state and the motor rotates at a low speed to medium speed. [Figure 8] It is an explanatory diagram showing an operation example of a motor when the pump is in a normal state and the motor rotates at a high speed. [Figure 9] It is an explanatory diagram showing an operation example of a motor when air biting occurs in the pump and the motor rotates at a high speed. [Figure 10] It is an explanatory diagram showing an example of setting the first threshold value. [Figure 11] It is a flowchart of the main process. [Figure 12] It is a flowchart of the process during stop. [Figure 13] It is a flowchart of the process during operation. [Figure 14] It is a flowchart of the air biting detection process of the first embodiment. [Figure 15] It is a flowchart of the continuation determination process. [Figure 16] It is a flowchart of the air biting detection process of the second embodiment. [Figure 17] It is a flowchart of the air biting detection process of the third embodiment.

Modes for Carrying Out the Invention

[0011] [1. Summary of Embodiments] In the present disclosure, terms such as "first", "second", etc. are only intended to distinguish elements from each other, and are not intended to limit the order or number of elements. Therefore, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. In addition, the first element may be provided without the second element, and similarly, the second element may be provided without the first element.

[0012] Some embodiments may provide an electric lubricant dispenser comprising at least any one of the following. · Feature 1: A motor. · Feature 2: A pump. · Feature 3: The pump is configured to be driven by the motor. · Feature 4: The pump is configured to discharge a lubricant. · Feature 5: A drive circuit. · Feature 6: The drive circuit is configured to drive the motor. · Feature 7: A control circuit. · Feature 8: The control circuit is configured to control the drive circuit to rotate the motor. · Feature 9: The control circuit is configured to perform a predetermined process based on the fact that the actual operation amount satisfies a predetermined requirement during the driving of the motor. · Feature 10: The actual operation amount indicates the actual rotation speed of the motor or the magnitude of the fluctuation of the actual rotation speed. The actual rotation speed is the actual rotation speed. The actual rotation speed may be defined as a scalar quantity without considering the rotation direction. · Feature 11: The predetermined requirement indicates that gas (or air bubbles) is mixed into the pump.

[0013] An electric lubricant dispenser having at least Features 1 to 11 can appropriately detect that gas is mixed into the pump. The motor is in the form of an electric motor. The motor may be configured to generate a driving force (or a rotational driving force). The pump may be configured to directly or indirectly receive the driving force of the motor and be driven by the driving force. Examples of the motor include a DC motor, an AC motor, and a stepping motor. Examples of the DC motor include a brushless motor (or a brushless DC motor) and a brushed DC motor.

[0014] Examples of the lubricant include a liquid lubricant and a semi-solid lubricant. Examples of the liquid lubricant include lubricating oil. Examples of the semi-solid lubricant include grease. That is, examples of the electric lubricant dispenser include an electric grease gun.

[0015] The pump may be configured to receive a lubricant and discharge the received lubricant. The lubricant may be introduced into the pump (i.e., received) by pressure applied to the pump outside the pump. Alternatively, the pump may be configured to generate negative pressure within the pump and use that negative pressure to receive (i.e., draw in) the lubricant.

[0016] Pumps can include any form of pump. Examples of pumps include positive displacement pumps. Examples of positive displacement pumps include reciprocating pumps and rotary pumps. Examples of reciprocating pumps include plunger pumps configured with a plunger that reciprocates, and diaphragm pumps configured with a diaphragm that reciprocates. Examples of pumps may also include non-positive displacement pumps.

[0017] The drive circuit may include multiple switching elements connected to the motor. Examples of drive circuits include full-bridge and half-bridge circuits. A full-bridge circuit may be connected to a three-phase motor. A three-phase motor has (i) three terminals configured to receive power, and (ii) is configured to rotate by the power received. The aforementioned brushless motor is a three-phase motor.

[0018] A full-bridge circuit may have six switching elements. Examples of the six switching elements include semiconductor switches and mechanical relays. Examples of semiconductor switches include field-effect transistors (FETs), bipolar transistors, insulated-gate bipolar transistors (IGBTs), thyristors, and solid-state relays (SSRs).

[0019] The six switching elements may include three high-side switches and three low-side switches. The three high-side switches are electrically connected to the positive terminal of the power supply and to the three terminals of the motor, respectively. The three low-side switches are electrically connected to the negative terminal of the power supply and to the three terminals of the motor, respectively. The three high-side switches may be arranged to conduct or interrupt the three positive-side current paths, respectively. The three positive-side current paths electrically connect the three terminals of the motor to the positive terminal of the power supply, respectively. The three low-side switches may be arranged to conduct or interrupt the three negative-side current paths, respectively. The three negative-side current paths electrically connect the three terminals of the motor to the negative terminal of the power supply, respectively.

[0020] The specified requirements may indicate that there is a possibility of gas contamination in the pump. That is, the actual operating volume meeting the specified requirements means that there is gas contamination in the pump, or the pump It could mean that there is a possibility that gas is mixed in. Alternatively, the statement "there is gas mixed in the pump" itself could encompass the meaning of "there is a possibility that gas is mixed in the pump."

[0021] The presence of gas in a pump may include (i) gas being present in the lubricant inside the pump, (ii) gas being present in the discharge that is about to be discharged by the pump, and / or (iii) gas being present in the container (e.g., the chamber described below) in which the lubricant is contained within the pump.

[0022] The prescribed procedure may be any procedure that corresponds to the presence of gas in the pump. The prescribed procedure may also be a procedure that should be performed or is preferable to be performed when gas is present in the pump. When gas is present in the pump, the lubricant may not be discharged properly. Specifically, the amount of lubricant discharged may decrease or the lubricant may not be discharged at all. Therefore, the prescribed procedure may be a procedure that corresponds to a state in which the lubricant may not be discharged properly, that is, a procedure that should be performed or is preferable to be performed in that state. Examples of the prescribed procedure are described later.

[0023] In one embodiment, the control circuit may be integrated into a single electronic unit, a single electronic device, or a single circuit board. In one embodiment, the control circuit may be a combination of two or more electronic circuits, two or more electronic units, or two or more electronic devices, individually provided on or within the electric lubricant dispenser.

[0024] In one embodiment, the control circuit may comprise a microcomputer (or microcontroller or microprocessor), wired logic, application-specific integrated circuits (ASICs), application-specific general-purpose products (ASSPs), programmable logic devices (PLDs) (such as field-programmable gate arrays (FPGAs)), discrete electronic components, and / or a combination thereof.

[0025] In one embodiment, the electric lubricant dispenser may be handheld (in other words, portable). That is, the electric lubricant dispenser may have a grip configured to be held by the user of the electric lubricant dispenser. The electric lubricant dispenser may be used while the grip is held by the user.

[0026] One embodiment may include, in addition to or instead of, at least one of the above features 1 to 11, at least one of the following: Feature 12: Actual operating volume includes the amplitude of the actual rotational speed. Feature 13: The predetermined requirement includes the condition that the maximum value of the amplitude within the predetermined driving period is less than or equal to a first threshold.

[0027] An electric lubricant dispenser possessing at least features 1-13 can accurately detect the presence of gas in the pump. The above feature 13 may be rephrased as the predetermined requirement being met in accordance with the fact that the maximum value of the amplitude within a predetermined driving period is less than or equal to a first threshold. The first threshold may be determined to be a value smaller than the range of amplitude that can occur in a normal state (e.g., its minimum value) and larger than the range of amplitude that can occur in an abnormal state (e.g., its maximum value). A normal state corresponds to a state in which no gas is mixed into the pump, and an abnormal state corresponds to a state in which gas is mixed into the pump. The amplitude of the actual rotational speed may be defined as the difference between the maximum and minimum values ​​of the actual rotational speed that changes over time. The maximum value of the amplitude is the difference between the maximum and minimum values ​​of the actual rotational speed within a predetermined driving period.

[0028] The predetermined drive period is a predetermined period of time while the motor is running. If the pump is configured to repeat a predetermined operation, the predetermined drive period may include at least the period during which that predetermined operation is performed.

[0029] One embodiment may include, in addition to or instead of, at least one of the features 1 to 13 described above, at least one of the following: Feature 14: The actual operating amount includes the absolute value of the derivative of the actual rotational speed. Feature 15: The specified requirement includes the condition that the maximum value of the absolute value within the specified drive period is less than or equal to the second threshold.

[0030] An electric lubricant dispenser possessing at least features 1-11, 14, and 15 can accurately detect the presence of gas in the pump. The above feature 15 may be rephrased as the predetermined requirement being satisfied in accordance with the fact that the maximum value of the absolute value within a predetermined driving period is less than or equal to the second threshold. The predetermined requirement may be rephrased as the absolute value of the derivative of the actual rotational speed not exceeding the second threshold throughout the predetermined driving period.

[0031] The second threshold may be determined to be a value smaller than the range of absolute values ​​that can occur under normal conditions (e.g., its minimum value) and larger than the range of absolute values ​​that can occur under abnormal conditions (e.g., its maximum value).

[0032] The derivative of the actual rotational speed may be calculated in any way. The derivative may be calculated, for example, based on the time derivative. That is, the amount of change in the actual rotational speed per predetermined unit time may be calculated as the derivative. Alternatively, for example, the derivative may be calculated based on the rotational angle derivative. That is, the amount of change in the actual rotational speed while the motor rotates by a predetermined unit rotational angle may be calculated as the derivative.

[0033] One embodiment may include, in addition to or instead of, at least one of the above features 1 to 15, at least one of the following: Feature 16: Actual operating volume includes actual rotational speed. Feature 17: The specified requirements include the minimum value of the actual rotational speed within the specified drive period being equal to or greater than the third threshold.

[0034] An electric lubricant dispenser possessing at least features 1-11, 16, and 17 can accurately detect the presence of gas in the pump. The above feature 17 may be rephrased as the predetermined requirement being met in accordance with the minimum value of the actual rotational speed within a predetermined drive period being greater than or equal to the third threshold. The predetermined requirement may be rephrased as the actual rotational speed not falling below the third threshold throughout the predetermined drive period. The third threshold may be determined to be greater than the range of actual rotational speeds that can occur under normal conditions (e.g., its maximum value) and less than the range of actual rotational speeds that can occur under abnormal conditions (e.g., its minimum value).

[0035] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 17: Feature 18: The control circuit is configured to change the first threshold value according to the operating state of the electric lubricant dispenser.

[0036] An electric lubricant dispenser possessing at least features 1-13,18 can more accurately detect the presence of gas in the pump. The operating state can include any state that affects the actual rotational speed. In other words, the operating state is This may include any state in which the actual rotational speed may change in response to the change in the operating state.

[0037] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 18: Feature 19: The control circuit is configured to change the second threshold value according to the operating state of the electric lubricant dispenser.

[0038] Electric lubricant dispensers possessing at least features 1-11, 14, 15, and 19 can more accurately detect the presence of gas in the pump. One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 19: Feature 20: The control circuit is configured to change the third threshold value according to the operating state of the electric lubricant dispenser.

[0039] Electric lubricant dispensers possessing at least features 1-11, 16, 17, and 20 can more accurately detect the presence of gas in the pump. One embodiment may include, in addition to or instead of, at least one of the features 1 to 20 described above, at least one of the following: Feature 21: The control circuit is configured to set a target rotational speed. The target rotational speed is the target value for the motor's rotational speed. Feature 22: The control circuit is configured to control the drive circuit so that the actual rotational speed matches the target rotational speed (i.e., the set target rotational speed). Feature 23: The aforementioned operating state includes the target rotational speed.

[0040] An electric lubricant dispenser having at least features 1-13, 18, 21-23, an electric lubricant dispenser having at least features 1-11, 14, 15, 19, 21-23, and an electric lubricant dispenser having at least features 1-11, 16, 17, 20-23 can more accurately detect the presence of gas in the pump.

[0041] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 23: Feature 24: The control circuit is configured to set the third threshold to a value smaller than the target rotational speed.

[0042] An electric lubricant dispenser possessing at least features 1-11, 16, 17, and 20-24 can more accurately detect the presence of gas in the pump. One embodiment may include, in addition to or instead of, at least one of the features 1 to 24 described above, at least one of the following: Feature 25: The control circuit is configured to control the drive circuit by outputting a pulse-width modulated signal with a duty cycle to the drive circuit. Feature 26: The drive circuit is configured to receive a pulse width modulated signal and drive the motor according to the received pulse width modulated signal. Feature 27: The aforementioned operating state includes the duty cycle.

[0043] An electric lubricant dispenser having at least features 1-13, 18, 25-27, an electric lubricant dispenser having at least features 1-11, 14, 15, 19, 25-27, and an electric lubricant dispenser having at least features 1-11, 16, 17, 20, 25-27 can more accurately detect the presence of gas in the pump.

[0044] The drive circuit is configured to drive the motor by supplying power to the motor according to the duty cycle. This may be done. Specifically, the drive circuit may be configured to increase the power as the duty cycle increases. The duty cycle may increase as the target rotational speed increases.

[0045] If the drive circuit includes the aforementioned plurality of switch elements, at least one of the plurality of switch elements may be configured to (i) receive a pulse width modulated signal and (ii) turn on or off (and thereby conduct or interrupt the corresponding current path) according to its duty cycle. That is, the larger the duty cycle, the longer the period during which it is turned on (i.e., the corresponding current path is conducted), and as a result the power supplied to the motor (and thus the motor output and / or actual rotational speed) may increase.

[0046] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 27: Feature 28: The aforementioned operating state includes the actual rotational speed.

[0047] An electric lubricant dispenser having at least features 1-13, 18, and 28, an electric lubricant dispenser having at least features 1-11, 14, 15, 19, and 28, and an electric lubricant dispenser having at least features 1-11, 16, 17, 20, and 28 can more accurately detect the presence of gas in the pump.

[0048] The control circuit may set the thresholds to be set (i.e., the first threshold, the second threshold, and / or the third threshold) in any way according to the operating state. The control circuit may set the thresholds according to a pre-prepared function that takes the operating state as a variable. The control circuit may set the thresholds by referring to a pre-prepared table or similar database that associates the operating state with the thresholds.

[0049] The control circuit may increase the first threshold and / or second threshold as the target rotational speed increases. In this case, in the region where the target rotational speed is greater than or equal to a predetermined value, the first threshold and / or second threshold may be decreased as the target rotational speed increases.

[0050] Similarly, the control circuit may increase the first threshold and / or second threshold as the duty cycle increases. In this case, in the region where the duty cycle is greater than or equal to a predetermined value, the first threshold and / or second threshold may be decreased as the duty cycle increases.

[0051] The control circuit may set the third threshold such that the difference between the target rotational speed and the third threshold decreases as the target rotational speed increases. Similarly, the control circuit may set the third threshold such that the difference between the target rotational speed corresponding to the duty cycle and the third threshold decreases as the duty cycle increases.

[0052] One embodiment may include, in addition to or instead of, at least one of the features 1 to 28 described above, at least one of the following: Feature 29: The control circuit is configured to obtain the temperature of the electric lubricant dispenser. Feature 30: The operating state includes the temperature.

[0053] An electric lubricant dispenser having at least features 1-13, 18, 29, 30, an electric lubricant dispenser having at least features 1-11, 14, 15, 19, 29, 30, and an electric lubricant dispenser having at least features 1-11, 16, 17, 20, 29, 30 can more accurately detect the presence of gas in the pump.

[0054] The control circuit may acquire the temperature of any (where) the electric lubricant dispenser. The temperature may be the temperature of the lubricant, or a temperature that can be considered to be the temperature of the lubricant (or a change in the lubricant).

[0055] In one embodiment, the electric lubricant dispenser may include a temperature sensor configured and positioned to directly or indirectly detect the temperature of the lubricant. The control circuit may vary a first threshold, a second threshold, and / or a third threshold depending on the temperature detected by the temperature sensor. The temperature sensor may be positioned in direct contact with the lubricant, in which case it can directly detect the temperature of the lubricant. Alternatively, the temperature sensor may be positioned at a distance from the lubricant. The temperature sensor may be in any form capable of detecting temperature. Examples of temperature sensors include positive temperature coefficient (PTC) thermistors, negative temperature coefficient (NTC) thermistors, and critical temperature resistor (CTR) thermistors.

[0056] If a particular embodiment has the above-described feature 29, that embodiment may further have at least one of the following: Feature 31: The control circuit is configured to decrease the first threshold as the acquired temperature increases. Feature 32: The control circuit is configured to decrease the second threshold as the acquired temperature increases. Feature 33: The control circuit is configured to increase the third threshold as the acquired temperature increases.

[0057] Electric lubricant dispensers having at least features 1-13, 18, 29-31, electric lubricant dispensers having at least features 1-11, 14, 15, 19, 29, 30, 32, and electric lubricant dispensers having at least features 1-11, 16, 17, 20, 29, 30, 33 can more accurately detect the presence of gas in the pump.

[0058] The aforementioned operating conditions may include more than the target rotational speed, duty cycle, actual rotational speed, and temperature described above. Examples of the aforementioned operating conditions include the magnitude of the voltage applied from the drive circuit to the motor, or physical quantities that indirectly indicate the magnitude of that voltage. If the drive circuit is configured to apply the voltage of a power source (e.g., a battery) to the motor, the operating conditions may include the battery voltage. In this case, as the battery voltage decreases, the voltage applied to the motor also decreases. Therefore, the first threshold may be set such that the first threshold decreases as the battery voltage decreases. The same applies to the second and third thresholds. One embodiment may include a voltage detector configured to detect the battery voltage. The voltage detector may be configured to (i) receive the battery voltage and (ii) output a voltage detection signal to a control circuit corresponding to the magnitude of that voltage. The control circuit may (i) obtain the magnitude of the battery voltage based on the voltage detection signal from the voltage detector and (ii) set a first threshold (or a second or third threshold) based on the obtained magnitude.

[0059] One embodiment may include, in addition to or instead of, at least one of the features 1 to 33 described above, at least one of the following: Feature 34: The electric lubricant dispenser is equipped with an alert unit. Feature 35: The notification unit is configured to notify information indicating that gas is mixed into the pump. Feature 36: The predetermined process includes broadcasting the information via the notification unit.

[0060] In an electric lubricant dispenser having at least features 1-11, 34-36, the user of the electric lubricant dispenser can easily know that gas is mixed into (or may be mixed into) the pump. The notification unit may notify the information in any way. The notification unit For example, the information may be configured to be displayed in a visible manner. The notification unit may be configured to output the information by sound in a way that makes it recognizable at a vertex angle.

[0061] One embodiment may include, in addition to or instead of, at least one of the features 1 to 36 described above, at least one of the following: Feature 37: The pump is configured to repeatedly perform a predetermined dispensing action for dispensing lubricant. Feature 38: The control circuit is configured to accumulate (in other words, cumulatively add up) the actual number of discharges, which is the number of times the predetermined discharge operation has been performed by the pump while the motor is running. Feature 39: The control circuit is configured to stop the motor based on when the actual number of discharges reaches the target number of discharges. Feature 40: The predetermined process includes temporarily suspending the accumulation of the actual number of discharges.

[0062] An electric lubricant dispenser having at least features 1-11, 37-40 can suppress or prevent the actual amount of lubricant dispensed until the motor is stopped from being less than the amount corresponding to the target number of dispenses. The dispensing operation may include receiving the lubricant and dispensing the received lubricant.

[0063] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 40: Feature 41: The control circuit is configured to temporarily stop accumulating the actual number of discharges, and then resume accumulating the actual number of discharges based on the fact that the actual operating amount no longer meets the predetermined requirements.

[0064] An electric lubricant dispenser possessing at least features 1-11, 37-41 can accurately dispense an amount of lubricant corresponding to the target number of discharges, even if gas is temporarily mixed into the pump while the motor is running.

[0065] One embodiment may include, in addition to or instead of, at least one of the features 1 to 41 described above, at least one of the following: Feature 42: The pump includes a chamber configured to contain a lubricant. The chamber may be configured to contain the lubricant received by the pump. Feature 43: The pump has a discharge port that communicates with the chamber. Feature 44: The pump is equipped with a plunger. Feature 45: The plunger is (i) located within a chamber and (ii) reciprocated within the chamber by a motor to discharge the lubricant from the chamber through a discharge port. The plunger may be reciprocated by a motor (or by the driving force of a motor).

[0066] An electric lubricant dispenser having at least features 1-11 and 42-45 can properly detect the ingress of gas in a plunger-type reciprocating pump. The aforementioned statement that "gas is present in the pump" may include the presence of gas in the chamber. The electric lubricant dispenser may include a converter that converts rotational motion into linear motion. The converter (i) is directly or indirectly connected to the motor and the reciprocating member, (ii) receives the rotation of the motor, and (iii) converts that rotation into the reciprocating motion of the reciprocating member. The converter may be one of several components that make up the pump.

[0067] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 45: Feature 46: The predetermined drive period includes the period during which the plunger makes one round trip within the chamber.

[0068] An electric lubricant dispenser having at least features 1-13, 42-46 can appropriately and efficiently detect the inclusion of gas in a plunger reciprocating pump. The aforementioned presence of gas in the pump may include (i) the presence of gas in the chamber, and / or (ii) the presence of gas in the discharge from the chamber that is about to be discharged by the plunger.

[0069] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 46: Feature 47: A predetermined discharge operation includes the plunger making one back-and-forth motion within the chamber.

[0070] An electric lubricant dispenser possessing at least features 1-11, 37-40, 42-45, and 47 can appropriately dispense an amount of lubricant corresponding to the target number of dispensing cycles. One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 47: Feature 48: The control circuit is configured to stop the motor when the actual operating amount has remained in a state that meets predetermined requirements for a predetermined period of time while the motor is running.

[0071] In electric lubricant dispensers that possess at least features 1-11,48, the user can take appropriate action in the event of a persistent condition in which gas is present (or potentially present).

[0072] In one embodiment, the motor may be stopped without waiting for a predetermined period of time to continue once a predetermined requirement is met. One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 48: Feature 49: The control circuit is configured to detect whether gas is present in the pump (or potentially present) and / or whether the pump is about to discharge the gas, depending on whether the predetermined requirements are met while the motor is running.

[0073] Electric lubricant dispensers possessing at least features 1-11,49 allow for various responses to be taken in response to the detection of gas contamination. One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 49: Feature 50: Lubricants are in a semi-solid form. An electric lubricant dispenser having at least features 1 to 11, 50 can properly detect when gas is mixed into a semi-solid form of lubricant.

[0074] One embodiment may include, in addition to or instead of, at least one of the above-described features 1 to 50: Feature 51: The lubricant contains grease.

[0075] An electric lubricant dispenser having at least features 1-11,51 can properly detect if gas is mixed into the grease. In some embodiments, the lubricant may be in liquid or solid form.

[0076] One embodiment may provide a method for dispensing lubricant from an electric lubricant dispenser, comprising at least one of the following: Feature 52: The pump of the electric lubricant dispenser is configured to dispense lubricant. To drive the lubricant dispenser using its motor. Feature 53: During motor operation, the electric lubricant dispenser performs a predetermined process based on the fact that the actual operating amount, which indicates the actual rotational speed of the motor or the magnitude of fluctuations in the actual rotational speed, meets the predetermined requirements indicating that gas is mixed into the pump.

[0077] A method having at least features 52 and 53 can adequately detect the presence of gas in the pump. In one embodiment, the above features 1 to 53 may be combined in any combination.

[0078] In one embodiment, any of the above features 1 to 53 may be excluded. [2. Specific exemplary embodiments] The following exemplary embodiment provides an electric lubricant dispenser 1 shown in Figure 1. The electric lubricant dispenser 1 is configured to dispense lubricant. Specifically, the electric lubricant dispenser 1 of this embodiment is an electric grease gun configured to dispense grease.

[0079] For the sake of clarity, the directions of the electric lubricant dispenser 1 are defined as shown in Figure 1 and subsequent figures. Specifically, "up" (upward direction), "down" (downward direction), "right" (rightward direction), "left" (leftward direction), "forward" (forward direction), and "backward" (backward direction) are defined. These directions are used merely to facilitate an easy understanding of the structure of the electric lubricant dispenser 1 and are not intended to limit the orientation of the electric lubricant dispenser 1. The electric lubricant dispenser 1 can be oriented in any direction.

[0080] [2-1. First Embodiment] (2-1-1) Mechanical configuration of electric lubricant dispenser As shown in Figures 1 and 2, the electric lubricant dispenser 1 of this first embodiment includes a housing 2. The housing 2 comprises a first split housing 2a and a second split housing 2b that are joined together.

[0081] The housing 2 has a motor housing 4 in its center in the height direction. The height direction corresponds to the direction from the bottom to the top or from the top to the bottom of the housing 2. In this first embodiment, the motor housing 4 is cylindrical and extends in the length direction. The length direction corresponds to the direction from the front to the rear or from the rear to the front of the housing 2. The motor housing 4 houses a motor 20. The motor 20 is an electric motor.

[0082] The housing 2 is equipped with a grip 5 on its upper part. In this first embodiment, the grip 5 extends in the longitudinal direction and is bent downward. The motor housing 4 is provided with a front coupling portion 6 at its front end. The front coupling portion 6 is coupled to the front end of the grip 5. The motor housing 4 is provided with a rear coupling portion 7 at its rear end. The rear coupling portion 7 is coupled to the rear end of the grip 5. In this first embodiment, the rear coupling portion 7 rises upward so as to form a space between the motor housing 4 and the grip 5.

[0083] The electric lubricant dispenser 1 is equipped with a trigger switch 8 housed within the grip 5. The electric lubricant dispenser 1 is also equipped with a trigger 9 for the user of the electric lubricant dispenser 1 to manually operate the trigger switch 8.

[0084] Trigger 9 is pulled by the user to drive the motor 20 (i.e., to dispense grease). Trigger 9 is configured to be displaceable between an initial position and a maximum position. When trigger 9 is not manually operated, it is in the initial position. In response to manual operation, trigger 9 moves from the initial position towards the maximum position.

[0085] When the trigger 9 is located between the initial position and the minimum position, the trigger switch 8 is off and the motor 20 is stopped. The minimum position is located between the initial position and the maximum position. When the trigger 9 is located between the minimum position and the maximum position, the trigger switch 8 is on and the motor 20 is rotatable. In this first embodiment, the trigger 9 protrudes downward from the grip 5.

[0086] The grip 5 is equipped with a light 10 on its front surface. In this first embodiment, the light 10 is equipped with a light-emitting diode (LED), which is not shown, as a light source. The grip 5 is equipped with an operation panel 70 on its front upper surface. The operation panel 70 is configured to be manually operated by the user to turn the light 10 on or off, or to change the settings of the electric lubricant dispenser 1.

[0087] The grip 5 is equipped with a first lock button 12 in front of the trigger 9. The first lock button 12 is configured to be pressed by the user to lock the trigger 9 in its maximum position. The grip 5 is equipped with a second lock button 13 below the first lock button 12. The second lock button 13 is configured to be pressed by the user to lock the trigger 9 in its initial position (i.e., unpulled position).

[0088] The rear coupling portion 7 is provided with a battery holding portion 14 at its rear end. The battery holding portion 14 is configured so that the battery pack 15 can be detachably attached to it. In this first embodiment, the battery holding portion 14 is configured such that the battery pack 15 is attached to the battery holding portion 14 by sliding the battery pack 15 from above to below at its rear end.

[0089] The battery pack 15 includes a battery (not shown) inside. In this first embodiment, the battery has a rated voltage of 36 volts. The battery pack 15 supplies power from the battery to the electric lubricant dispenser 1 via the battery holder 14.

[0090] The battery holder 14 includes a terminal block 16 inside. The terminal block 16 is configured to be electrically connected to the battery pack 15 mounted in the battery holder 14. In this first embodiment, the terminal block 16 extends in the height direction.

[0091] The battery holder 14 houses the control unit 17 in front of the terminal block 16. In this first embodiment, the control unit 17 extends in the height direction. The control unit 17 includes a control circuit board 18.

[0092] In this first embodiment, the motor 20 is an inner rotor type brushless motor (more specifically, a three-phase brushless DC motor). In another embodiment, the motor 20 may be any other type of motor (for example, a brushed DC motor).

[0093] The motor 20 includes a stator 21. The stator 21 has three lead wires 27 (Figure 2 shows only one lead wire 27). The stator 21 has a first insulator 23A at its front end. The stator 21 has a second insulator 23B at its rear end.

[0094] The stator 21 comprises three coils 24 wound around a first insulator 23A and a second insulator 23B. The second insulator 23B has six terminals (not shown) fused to the ends of the wires of these coils 24.

[0095] The second insulator 23B includes a short-circuit member 25. The short-circuit member 25 comprises three insert-molded short-circuit fittings 26 (Figure 2 shows only two short-circuit fittings 26). These short-circuit fittings 26 electrically connect the terminals of the second insulator 23B so that the coil 24 described above forms a delta configuration (or delta connection). The coil 24 described above may also form a star configuration (or star connection).

[0096] The stator 21 includes a sensor circuit board 28 between the second insulator 23B and the short-circuit member 25. The sensor circuit board 28 includes first to third rotational position sensors 28A to 28C (see Figure 6). In this first embodiment, the first to third rotational position sensors 28A to 28C are Hall sensors, but are not limited to Hall sensors. The first to third rotational position sensors 28A to 28C are connected to three signal lines 29 (Figure 2 shows only one signal line 29). The lead wires 27 and signal lines 29 are connected to the control circuit board 18 of the control unit 17.

[0097] The motor 20 has a rotor 22 inside a stator 21. The rotor 22 has a rotating shaft 30 at its center. The rotating shaft 30 has two or more permanent magnets 31 embedded in its outer circumferential wall.

[0098] The first to third rotational position sensors 28A to 28C (i) are arranged around the rotor 22 and (ii) each output first to third rotational signals corresponding to the rotational position of the rotational axis 30 (and consequently the rotational position of the rotor 22).

[0099] The rotating shaft 30 is equipped with a fan 32 attached to its front end. In this first embodiment, the fan 32 extends perpendicular to the rotating shaft 30. The rear coupling portion 7 houses the first bearing 35 behind the short-circuiting member 25. The first bearing 35 rotatably supports the rear end of the rotating shaft 30.

[0100] The motor housing 4 includes a gear housing 40 in front of the motor 20. In this first embodiment, the gear housing 40 is cylindrical. The gear housing 40 has an opening at its rear end. The gear housing 40 includes a bracket plate 41 attached to this opening. The rotating shaft 30 protrudes into the gear housing 40 through the bracket plate 41. The bracket plate 41 holds a second bearing 42. The second bearing 42 rotatably supports the front end of the rotating shaft 30.

[0101] The gear housing 40 is equipped with a spindle 44 at its front end. The gear housing 40 houses a transmission mechanism 43. The transmission mechanism 43 is connected to the rotating shaft 30 and transmits the rotation of the rotating shaft 30 to the pump 60 described later via the spindle 44. The transmission mechanism 43 is configured to (i) receive the rotation of the rotating shaft 30 and (ii) rotate the spindle 44 at a rotational speed lower than the rotational speed of the rotating shaft 30. The transmission mechanism 43 may include planetary gears.

[0102] Housing 2 includes a crank housing 45 at the front end of the gear housing 40. In this first embodiment, the crank housing 45 extends in the height direction. The spindle 44 protrudes from the gear housing 40 into the crank housing 45.

[0103] The crank housing 45 houses a crank disc 46 located at the front end of the spindle 44. The crank disc 46 is equipped with an eccentric pin 47 that protrudes forward. The crank housing 45 is equipped with a slider 48 in front of the crank disc 46. The slider 48 is equipped with an elongated hole 48A that extends in the width direction. The width direction corresponds to the direction from right to left or left to right of the housing 2. The elongated hole 48A is equipped with an eccentric pin 47 A slider 48 is inserted. The slider 48 is connected to the plunger 50 at the center of its lower end. The plunger 50 has an upper end connected to the slider 48 and extends downward.

[0104] The crank housing 45 includes a slider guide 49 that supports the slider 48 so that it can move up and down. The slider 48 and slider guide 49 are also shown in Figure 3. The slider 48 is movable in the height direction along the slider guide 49.

[0105] In the crank housing 45 configured in this way, when the crank disc 46 rotates together with the spindle 44, the eccentric pin 47 undergoes eccentric motion. The vertical stroke of the eccentric pin 47 causes the slider 48 to reciprocate up and down, and the plunger 50 also reciprocates up and down. In other words, the crank disc 46 and the slider 48 convert the rotational motion of the motor 20 into linear reciprocating motion.

[0106] The crank housing 45 is equipped with a front holder 51 at its lower part. The housing 2 is equipped with a rear holder 52 behind the front holder 51 and below the motor housing 4. The rear holder 52 is equipped with two legs 53 that protrude downward at its front and rear ends.

[0107] The electric lubricant dispenser 1 comprises a tank 54 supported by a front holder 51 and a rear holder 52. The tank 54 has an open front end. The tank 54 reaches the rear surface of the front holder 51 through the rear holder 52. The front end of the tank 54 is screwed into the rear surface of the front holder 51. In other words, the tank 54 extends longitudinally below the motor housing 4.

[0108] The tank 54 houses a rod 55. The rod 55 extends from the rear end of the tank 54 to the front end of the tank 54. The rod 55 holds the piston 56 so that it can move along the rod 55. The rod 55 has a rear end that protrudes from the tank 54. The tank 54 has a handle 57 attached to the rear end of the rod 55. The tank 54 houses a coil spring 58. The coil spring 58 is located behind the piston 56 and biases the piston 56 forward. The tank 54 houses a grease-filled cartridge (not shown) in front of the piston 56. This cartridge is pressed against the piston 56, supplying grease into the front holder 51.

[0109] The front holder 51 is equipped with a pump 60. The pump 60 is equipped with the plunger 50 described above. The pump 60 is equipped with an upper cylinder portion 60A and a lower cylinder portion 60B. The upper cylinder portion 60A and the lower cylinder portion 60B form a chamber 63. The plunger 50 is located inside the chamber 63.

[0110] Chamber 63 has an inlet hole 63A between the upper cylindrical portion 60A and the lower cylindrical portion 60B. Chamber 63 communicates with tank 54 through the inlet hole 63A. Grease is supplied from the cartridge into chamber 63 through the inlet hole 63A.

[0111] The upper cylinder portion 60A is equipped with a seal ring 61A at its top. The plunger 50 passes through the seal ring 61A. The seal ring 61A prevents or suppresses grease in the chamber 63 from leaking out of the upper cylinder portion 60A upward.

[0112] The lower cylinder portion 60B is provided with a discharge passage 66. The discharge passage 66 (i) communicates with the chamber 63 via a check valve 64 (described later), and (ii) extends in the longitudinal direction. The front holder 51 is provided with a front cylinder portion 60C at its front end. The front cylinder portion 60C protrudes forward from the front holder 51. The discharge passage 66 passes through the center of the front cylinder portion 60C. The discharge passage 66 is provided with a discharge port 66A at its front end. The front cylinder portion 60C is connected to a hose 68. The lubricant is discharged from outlet 66A through hose 68 to the outside of the electric lubricant dispenser 1.

[0113] The pump 60 is equipped with the aforementioned check valve 64 at the bottom of the chamber 63. The check valve 64 allows grease to flow out of the chamber 63 into the discharge passage 66, while suppressing or preventing backflow of grease from the discharge passage 66 into the chamber 63.

[0114] The front cylinder portion 60C is equipped with a relief valve 69 on its right side. The relief valve 69 is configured to release the grease in the discharge passage 66 to the outside of the electric lubricant supply unit 1 when the pressure of the grease in the discharge passage 66 exceeds a predetermined pressure.

[0115] The front holder 51 is equipped with an air drain valve 67 at its front end. The air drain valve 67 is provided to release gas (e.g., air) inside the chamber 63 (more specifically near the inlet hole 63A) to the outside of the electric lubricant dispenser 1. When the air drain valve 67 is tightened, the chamber 63 is isolated from the outside of the electric lubricant dispenser 1. The electric lubricant dispenser 1 is normally used with the air drain valve 67 tightened. When the air drain valve 67 is loosened, the chamber 63 communicates with the outside of the electric lubricant dispenser 1. If gas is present in the chamber 63 at this time, that gas can be released to the outside of the electric lubricant dispenser 1 via the air drain valve 67.

[0116] (2-1-2) Mechanical operation of the electric lubricant dispenser In the electric lubricant dispenser 1 configured as described above, when the user pulls the trigger 9, the motor 20 rotates, and consequently, the rotating shaft 30 rotates.

[0117] The rotation of the rotating shaft 30 is transmitted to the spindle 44 via the transmission mechanism 43, and the crankcase 46 rotates together with the spindle 44. This causes the eccentric pin 47 to perform an eccentric motion. In response to the eccentric motion of the eccentric pin 47, (i) the slider 48 moves up and down along the slider guide 49, and (ii) this causes the plunger 50 to reciprocate up and down.

[0118] More specifically, as shown in Figure 3, the plunger 50 moves up and down through the first to fourth states in this order. Figure 3 schematically shows the position of the inlet hole 63A. The first state is when the slider 48 is in the process of moving upward. More specifically, the first state is when the slider 48 is in an intermediate position within its reciprocating range. Figure 2 shows the electric lubricant dispenser 1 in the first state. In the first state, as is clear from Figures 2 and 3, the plunger 50 is inserted into the lower cylinder portion 60B. When the motor 20 rotates further from the first state, it transitions to the second state.

[0119] The second state is when the slider 48 has reached the highest point in its reciprocating range. Before the slider 48 reaches the highest point, the lower end of the plunger 50 disengages from the lower cylinder 60B, thereby allowing grease to flow from the tank 54 into the chamber 63. In the second state, the lower end of the plunger 50 is either fully retracted into the upper cylinder 60A or slightly protruding downward from the upper cylinder 60A. If the motor 20 rotates further from the second state, the slider 48 moves downward, transitioning to the third state.

[0120] The third state is when the slider 48 is in the process of moving downward. More specifically, the third state is when the slider 48 is in an intermediate position within its reciprocating range. In the third state, as in the first state, the plunger 50 is inserted into the lower cylinder portion 60B. If the motor 20 rotates further from the third state, it transitions to the fourth state.

[0121] The fourth state is when the slider 48 has reached its lowest point within its reciprocating range. In the fourth state, the lower end of the plunger 50 has reached near the lower end of the chamber 63. When the motor 20 rotates further from this state, the slider 48 moves upward and transitions to the first state.

[0122] Between the second and fourth states, the plunger 50 moves downward. During this time, the grease in the chamber 63 is pressed against the bottom surface of the plunger 50 (i.e., the lower end surface; hereinafter referred to as the "plunger lower end surface"). As a result, the grease flows into the hose 68 via the check valve 64, the discharge passage 66, and the discharge port 66A, and is discharged from the hose 68 to the outside of the electric lubricant supply unit 1.

[0123] Thus, while the motor 20 is rotating, the slider 48 (and consequently the plunger 50) moves back and forth repeatedly, causing grease to be continuously discharged (or may be discharged) from the discharge port 66A. Grease is discharged each time the plunger 50 makes one back-and-forth motion. Therefore, one back-and-forth motion of the plunger 50 can be rephrased as one grease discharge operation. One back-and-forth motion of the plunger 50 (i.e., one discharge operation) is an example of a predetermined discharge operation in the summary of the embodiment.

[0124] Note that the motor 20 may rotate in the opposite direction to the operation example in Figure 3. In this case, the plunger 50 moves up and down through the fourth to first states in that order, thereby discharging grease in the same way as the operation example in Figure 3.

[0125] (2-1-3) Details of the control panel As shown in Figure 4, the control panel 70 includes a first switch 71. In this first embodiment, the first switch 71 and the second and third switches 72 and 73, which will be described later, are push-button switches. In another embodiment, the first to third switches 71 to 73 may be other types of manual switches.

[0126] Each time the first switch 71 is briefly pressed, the rotational speed level of the motor 20 is sequentially switched to one of several rotational speed levels (for example, four levels: levels 1 to 4). For each rotational speed level, the maximum rotational speed of the motor 20 is set. The maximum rotational speed increases in the order of, for example, level 1, level 2, level 3, and level 4.

[0127] The motor 20 is rotated up to the maximum rotational speed corresponding to the set rotational speed level. Specifically, for example, the target rotational speed is set up to the maximum rotational speed, depending on the operating mode and / or the amount (i.e., position) of the trigger 9, as described later. The motor 20 is controlled to maintain a constant rotational speed (in other words, speed feedback control) so that the actual rotational speed matches the target rotational speed.

[0128] When the first switch 71 is pressed and held, the light 10 turns on. After the light 10 turns on, the light 10 may turn off, for example, if (i) a predetermined time has elapsed or (ii) the first switch 71 is pressed and held again. A short press corresponds to an operation in which the switch is released before a certain period of time has elapsed since it was pressed. A long press corresponds to an operation in which the switch is pressed and held continuously for a certain period of time or longer before being released.

[0129] The control panel 70 includes a first display screen 74. The first display screen 74 displays information indicating the set rotation speed level (for example, a number from "1" to "4"). "1" to "4" represent the first to fourth levels, respectively. In this first embodiment, the first display screen 74 and the second and third display screens 75A and 75B, described later, are each 7-segment displays. In another embodiment, each of the first to third display screens 74, 75A, and 75B may be other types of display screens, including liquid crystal displays (LCDs).

[0130] The control panel 70 includes the aforementioned second switch 72 and third switch 73. Each time the second and third switches 72 and 73 are pressed simultaneously, the operating mode of the electric lubricant dispenser 1 is switched. In this first embodiment, the operating modes include a continuous discharge mode and an automatic discharge mode (or a quantitative discharge mode). In this first embodiment, each time the second and third switches 72 and 73 are pressed simultaneously, the operating mode alternately switches between the continuous discharge mode and the automatic discharge mode.

[0131] In continuous discharge mode, the motor 20 rotates continuously while the trigger 9 is pulled. In this first embodiment, the target rotational speed in continuous discharge mode changes depending on the position of the trigger 9. Specifically, the target rotational speed increases continuously or in steps as the trigger 9 moves from the minimum position to the target arrival position. More specifically, the target rotational speed increases from a predetermined minimum value (e.g., zero) towards a maximum rotational speed corresponding to a set rotational speed level. The target arrival position may be located between the minimum and maximum positions, or it may coincide with the maximum position. When the trigger 9 reaches the target arrival position, the target rotational speed reaches the maximum rotational speed corresponding to the set rotational speed level. If the trigger 9 is located between the target arrival position and the maximum position, the target rotational speed is maintained at the maximum rotational speed.

[0132] In addition, the target rotational speed in continuous discharge mode may be maintained at a constant rotational speed (for example, the maximum rotational speed corresponding to the set rotational speed level) regardless of the position of the trigger 9.

[0133] In automatic dispensing mode, the motor 20 starts rotating when the trigger 9 is pulled. After rotation begins, when the plunger 50 (in other words, the slider 48) has reciprocated a target number of times (in other words, when the predetermined dispensing operation has been performed a target number of times, or to put it another way, when an amount of grease corresponding to the target number of reciprocations has been dispensed), the motor 20 automatically stops, even if the trigger 9 is still pulled. The target number of reciprocations can be set to any value by the user.

[0134] In automatic dispensing mode, the target rotational speed is set to a constant rotational speed (for example, the maximum rotational speed corresponding to the set rotational speed mode) regardless of the position of trigger 9. However, the target rotational speed in automatic dispensing mode may change depending on the position of trigger 9, similar to continuous dispensing mode.

[0135] The control panel 70 is equipped with a setting count display screen 75. The setting count display screen 75 (i) comprises the aforementioned second display screen 75A and third display screen 75B, and (ii) is capable of displaying a two-digit number. When the operating mode is set to automatic discharge mode, the target number of round trips is displayed on the setting count display screen 75.

[0136] In this first embodiment, in automatic dispensing mode, any target number of round trips can be set, up to a predetermined maximum set number of 99 or less. The user can set the target number of round trips to any value by operating the second switch 72 or the third switch 73. Specifically, in automatic dispensing mode, each time the second switch 72 is pressed, the target number of round trips increases by one, and the increased target number of round trips is set as the new target number of round trips and displayed on the set number display screen 75. Conversely, in automatic dispensing mode, each time the third switch 73 is pressed, the target number of round trips decreases by one, and the decreased target number of round trips is set as the new target number of round trips and displayed on the set number display screen 75. The maximum set number of round trips can be determined in any way and may be set to 100 or more.

[0137] (2-1-4) Electrical configuration of the electric lubricant dispenser Referring to Figure 5, the electrical configuration of the electric lubricant dispenser 1 will be described. The electric lubricant dispenser 1 includes a control circuit board 18 with a ground. The electric lubricant dispenser 1 includes a power line Lp extending from the positive terminal of the battery pack 15 mounted in the battery holder 14 to the control circuit board 18. The electric lubricant dispenser 1 includes a ground line Ln extending from the negative terminal of the battery pack 15 mounted in the battery holder 14 to the ground on the control circuit board 18. The battery pack 15 applies its rated voltage between the power line Lp and the ground line Ln.

[0138] The electric lubricant dispenser 1 includes a power supply circuit 84. In this first embodiment, the power supply circuit 84 is located on the control circuit board 18. The power supply circuit 84 is connected to the power line Lp and to ground. The power supply circuit 84 generates a fixed DC voltage (hereinafter referred to as "power supply voltage") Vc based on the battery voltage supplied from the battery pack 15.

[0139] The electric lubricant dispenser 1 is equipped with a control circuit 80. The control circuit 80 is located on a control circuit board 18 and operates in response to a power supply voltage Vc. The control circuit 80 is a microcomputer comprising a CPU 80A and a semiconductor memory 80B. The semiconductor memory 80B includes ROM, RAM, and rewritable non-volatile memory. Non-volatile memory includes, for example, EEPROM, flash memory, ReRAM, FeRAM, etc. The various functions of the control circuit 80 are realized by the CPU 80A executing a program stored in the semiconductor memory 80B. When the CPU 80A executes this program, the method corresponding to this program is executed.

[0140] In another embodiment, the control circuit 80 may include an additional microcomputer. In yet another embodiment, some or all of the functions achieved by the CPU 80A may be achieved by one or more electronic components (e.g., integrated circuits). In yet another embodiment, the control circuit 80 may be a logic circuit (or wired logic connection) including two or more electronic components. In yet another embodiment, the control circuit 80 may include an ASIC and / or ASSP. In yet another embodiment, the control circuit 80 may include a programmable logic device on which a reconfigurable logic circuit can be constructed. An example of a programmable logic device is an FPGA.

[0141] The electric lubricant dispenser 1 includes a drive circuit 82 configured to drive a motor 20. In this first embodiment, the drive circuit 82 is located on a control circuit board 18. The drive circuit 82 is a three-phase full-bridge circuit, but is not limited to a three-phase full-bridge circuit. The drive circuit 82 includes first to third switches Q1 to Q3 located on the high side and fourth to sixth switches Q4 to Q6 located on the low side. The first to third switches Q1 to Q3 are connected to the power line Lp and the corresponding lead wires 27 of the motor 20, respectively, and function as so-called high-side switches. The fourth to sixth switches Q4 to Q6 are connected to the corresponding lead wires 27 and ground, respectively, and function as so-called low-side switches.

[0142] The first to sixth switches Q1 to Q6 each receive the first to sixth drive control signals from the control circuit 80 and turn on or off according to the respective drive control signals they receive. In this first embodiment, the first to sixth drive control signals may be pulse width modulated signals. The first to sixth switches Q1 to Q6 are semiconductor switches. Examples of semiconductor switches include field-effect transistors (FETs), bipolar transistors, and insulated-gate bipolar transistors (IGBTs).

[0143] When the motor 20 is driven, basically one of the high-side switches and one of the low-side switches are turned on. This allows the positive terminal of the battery to be connected to the high-side switch. Motor current flows to the negative terminal of the battery via the negative side switch, motor 20, and the negative side switch, causing motor 20 to rotate.

[0144] The electric lubricant dispenser 1 includes a sliding resistor 81 having a lever 81A. The lever 81A has a displaceable first end and a second end connected to the control circuit 80. The sliding resistor 81 has a resistance value that changes depending on the position of the first end of the lever 81A. The second end of the lever 81A outputs a voltage (hereinafter referred to as "trigger voltage") of a magnitude corresponding to the resistance value to the control circuit 80. The first end of the lever 81A is displaced according to the position of the trigger 9 in the range from the initial position to the maximum position. For example, the resistance value of the sliding resistor 81 is minimum when the trigger 9 is in the initial position and increases as the trigger 9 approaches the maximum position from the initial position.

[0145] The electric lubricant dispenser 1 is equipped with first to fourth pull-up resistors R1 to R4. In this first embodiment, the first to fourth pull-up resistors R1 to R4 are located on the control circuit board 18. Each of the first to fourth pull-up resistors R1 to R4 has a first terminal connected to the power supply circuit 84 to receive the power supply voltage Vc from the power supply circuit 84. The first pull-up resistor R1 has a first terminal connected to the trigger switch 8 and a second terminal connected to the control circuit 80. The second pull-up resistor R2 has a first terminal connected to the first switch 71 and a second terminal connected to the control circuit 80. The third pull-up resistor R3 has a first terminal connected to the second switch 72 and a second terminal connected to the control circuit 80. The fourth pull-up resistor R4 has a first terminal connected to the third switch 73 and a second terminal connected to the control circuit 80. Each of the trigger switch 8, the first switch 71, the second switch 72, and the third switch 73 has a second terminal connected to ground on the control circuit board 18.

[0146] When the trigger switch 8, the first switch 71, the second switch 72, and the third switch 73 are off, the second terminals of the first to fourth pull-up resistors R1 to R4 have a voltage at the same level as the power supply voltage Vc (i.e., a high level). When the trigger switch 8, the first switch 71, the second switch 72, and the third switch 73 are on, the second terminals of the first to fourth pull-up resistors R1 to R4 have a voltage at the same level as ground (i.e., a low level). The first to fourth pull-up resistors R1 to R4 may have the same resistance value or may have different resistance values.

[0147] The control circuit 80 can detect whether the trigger 9, the first switch 71, the second switch 72, and the third switch 73 are being operated manually, based on the voltages at the second terminals of the first to fourth pull-up resistors R1 to R4. Specifically, if the voltages at the second terminals of the first to fourth pull-up resistors R1 to R4 are at a high level, the control circuit 80 detects that the trigger 9, the first switch 71, the second switch 72, and the third switch 73 are not being operated manually. If the voltages at the second terminals of the first to fourth pull-up resistors R1 to R4 are at a low level, the control circuit 80 detects that the trigger 9, the first switch 71, the second switch 72, and the third switch 73 are being operated manually.

[0148] The control circuit board 18 is connected to the first to third display screens 74, 75A, and 75B of the operation panel 70. The first to third display screens 74, 75A, and 75B operate by receiving a power supply voltage Vc from the control circuit board 18. In addition, the first to third display screens 74, 75A, and 75B each receive the first to third display control signals from the control circuit 80 and display information.

[0149] The control circuit board 18 is connected to the sensor circuit board 28. The first to third rotational position sensors 28A to 28C on the sensor circuit board 28 operate by receiving a power supply voltage Vc from the control circuit board 18. The first to third rotational position sensors 28A to 28C are connected to the control circuit 80 via signal lines 29 and output the first to third rotational signals to the control circuit 80. The three rotation signals are associated with each of the three phases of the motor 20 (i.e., U-phase, V-phase, and W-phase). The first to third rotation signals are, for example, sinusoidal signals. The voltage of each of the first to third rotation signals reverses from positive to negative or negative to positive each time the rotor 22 rotates 180 degrees in electrical angle. The first to third rotation signals have a phase difference of 120 degrees in electrical angle from each other.

[0150] In another embodiment, the sensor circuit board 28 may be configured to output a single rotation detection signal (e.g., a pulse signal) to the control circuit 80 instead of the first to third rotation signals. The rotation detection signal changes each time the rotor 22 rotates by 60 degrees in electrical angle.

[0151] The electric lubricant dispenser 1 includes a temperature sensor 100 connected to a control circuit 80. The temperature sensor 100 is provided to detect the temperature of the electric lubricant dispenser 1. More specifically, the temperature sensor 100 is provided to directly or indirectly detect the temperature of the grease. The temperature sensor 100 outputs a temperature detection signal indicating the detected temperature to the control circuit 80. The temperature sensor 100 may be in any form capable of detecting temperature. The temperature sensor 100 may include, for example, a positive temperature coefficient (PTC) thermistor, a negative temperature coefficient (NTC) thermistor, or a critical temperature resistor (CTR) thermistor.

[0152] The temperature sensor 100 may be positioned in any location that allows it to directly or indirectly detect the temperature (or level) of the grease. For example, the temperature sensor 100 may be positioned in a location that allows it to directly contact the grease. More specifically, the temperature sensor 100 may be positioned, for example, at the inlet of the pump 60 (e.g., the inlet hole 63A).

[0153] Alternatively, the temperature sensor 100 may be positioned in a location that does not come into contact with the grease. Specifically, the temperature sensor 100 may be positioned, for example, on the surface or inside the grip 5, around the front holder 51, or near the tank 54 in the housing 2.

[0154] (2-1-5) Functional configuration of an electric lubricant dispenser Referring to Figure 6, the functions of the control circuit 80 will be explained. The control circuit 80 includes the functions of a pull amount detection unit 77, a switch detection unit 78, a round trip count setting unit 83, a round trip count calculation unit 79, a display control unit 85, a speed setting unit 86, an operation mode setting unit 87, a timing unit 88, a round trip determination unit 89, an air entrapment detection unit 90, an operation control unit 91, and a motor drive control unit 92. In this first embodiment, these functions are incorporated into the control circuit 80 by software. In other words, these functions are realized by the CPU 80A executing the corresponding program (specifically, the main processing described later).

[0155] In another embodiment, at least one of the following functions may be incorporated into the control circuit 80 by hardware (electronic circuitry) rather than software: the pull amount detection unit 77, the switch detection unit 78, the number of round trips setting unit 83, the number of round trips calculation unit 79, the display control unit 85, the speed setting unit 86, the operation mode setting unit 87, the timing unit 88, the round trip determination unit 89, the air lock detection unit 90, the operation control unit 91, and the motor drive control unit 92.

[0156] The pull amount detection unit 77 receives a trigger voltage from the sliding resistor 81. Based on the trigger voltage, the pull amount detection unit 77 detects the actual pull amount of the trigger 9. The actual pull amount is the actual pull amount (i.e., the actual position). If the magnitude of the trigger voltage corresponds to the initial position of the trigger 9, the pull amount detection unit 77 detects an actual pull amount of zero. If the magnitude corresponds to the maximum position of trigger 9, the maximum actual pull amount is detected. If the magnitude of the trigger voltage corresponds to the intermediate position of trigger 9, the pull amount detection unit 77 detects the actual pull amount between zero and the maximum value. The intermediate position is between the initial position and the maximum position. The pull amount detection unit 77 outputs the detected actual pull amount to the speed setting unit 86.

[0157] The switch detection unit 78 detects the change from off to on and from on to off for each of the trigger switch 8, the first switch 71, the second switch 72, and the third switch 73. When the trigger switch 8 changes from off to on, the switch detection unit 78 outputs a first signal to the operation control unit 91 and the round-trip count calculation unit 79. The first signal indicates that the trigger switch 8 has changed from off to on. When the trigger switch 8 changes from on to off, the switch detection unit 78 outputs a second signal to the operation control unit 91 and the round-trip count calculation unit 79. The second signal indicates that the trigger switch 8 has changed from on to off. When the first switch 71 changes from off to on, the switch detection unit 78 outputs a third signal to the operation mode setting unit 87. The third signal indicates that the first switch 71 has changed from off to on. When the second switch 72 and the third switch 73 are simultaneously turned on, the switch detection unit 78 outputs a fourth signal to the operation mode setting unit 87. Simultaneous on means that the switches change from off to on at the same time or approximately at the same time. The fourth signal indicates that the second switch 72 and the third switch 73 have been turned on simultaneously.

[0158] The switch detection unit 78 outputs a fifth signal to the round-trip count setting unit 83 in response to the change of the second switch 72 from off to on while the third switch 73 is off. The fifth signal indicates that the second switch 72 has changed from off to on. The switch detection unit 78 outputs a sixth signal to the round-trip count setting unit 83 in response to the change of the third switch 73 from off to on while the second switch 72 is off. The sixth signal indicates that the third switch 73 has changed from off to on.

[0159] The operation mode setting unit 87 sets the rotation speed level of the motor 20 according to the input third signal. Specifically, each time the third signal is input, the operation mode setting unit 87 changes the rotation speed level in the following order: first level → second level → third level → fourth level → first level...

[0160] The operation mode setting unit 87 sets the operation mode of the electric lubricant dispenser 1 to either continuous discharge mode or quantitative discharge mode in response to the input of the fourth signal. Specifically, each time the fourth signal is input, the operation mode setting unit 87 alternately switches the operation mode between continuous discharge mode and quantitative discharge mode.

[0161] The operation mode setting unit 87 outputs the set operation mode to the speed setting unit 86, the number of reciprocations setting unit 83, the number of reciprocations calculation unit 79, and the operation control unit 91. Note that in Figure 6, the arrows from the operation mode setting unit 87 to the number of reciprocations setting unit 83 and the number of reciprocations calculation unit 79 are omitted. The operation mode setting unit 87 outputs the set rotation speed level to the speed setting unit 86 and the display control unit 85. Note that in Figure 6, the arrows from the operation mode setting unit 87 to the display control unit 85 are omitted.

[0162] The speed setting unit 86 sets the target rotational speed of the motor 20 based on the input actual grease dispensing amount, rotational speed level, and operating mode. It then notifies the operation control unit 91 and the air entrainment detection unit 90 of the set target rotational speed. The rotational speed of the motor 20 is proportional to the discharge speed. The discharge speed is the speed at which grease is discharged from the discharge port 66A, in other words, the amount of grease discharged per unit time. Therefore, setting the target rotational speed is equivalent to setting a target value for the discharge speed.

[0163] Specifically, when the operating mode is continuous discharge mode, the speed setting unit 86 sets the target rotational speed to a value within the settable range that corresponds to the actual discharge amount. The settable range is from the minimum value (e.g., zero) to the maximum rotational speed corresponding to the rotational speed level. On the other hand, when the operating mode is quantitative discharge mode, the speed setting unit 86 maintains the target rotational speed at a constant speed (e.g., the maximum rotational speed corresponding to the rotational speed level).

[0164] In this first embodiment, when the motor 20 is started, the target rotational speed is not immediately set to a predetermined value, but gradually increases toward the predetermined value. The predetermined value is the target rotational speed corresponding to the position of the trigger 9 in the continuous discharge mode, and the aforementioned constant target rotational speed in the automatic discharge mode. However, the target rotational speed may be immediately set to the predetermined value when the motor 20 is started.

[0165] The reciprocating count setting unit 83 sets the target number of reciprocating motions of the plunger 50 (in other words, the target number of dispensing operations) based on the input fifth and sixth signals when the operating mode is quantitative dispensing mode. Specifically, each time the fifth signal is input, the reciprocating count setting unit 83 increases the target number of reciprocating motions by one from the current value. Each time the sixth signal is input, the reciprocating count setting unit 83 decreases the target number of reciprocating motions by one from the current value. The target number of reciprocating motions may always be maintained at the latest value. Alternatively, it may be set to an initial value (e.g., zero) each time the battery pack 15 is attached to the electric lubricant dispenser 1 (i.e., each time the control circuit 80 is started). In this first embodiment, the target number of reciprocating motions is set to, for example, one of 0 to 99. The reciprocating count setting unit 83 outputs the set target number of reciprocating motions to the reciprocating count calculation unit 79. The target number of reciprocating motions is an example of the target number of dispensing operations in the summary of the embodiment.

[0166] The reciprocating determination unit 89 receives first to third rotation signals from first to third rotation position sensors 28A to 28C. Based on the first to third rotation signals, the reciprocating determination unit 89 counts the number of rotations of the motor 20. Based on the number of rotations of the motor 20 and the reduction ratio of the transmission mechanism 43, the reciprocating determination unit 89 determines whether the plunger 50 has completed one reciprocating motion (i.e., whether one discharge operation has been performed). Each time the reciprocating determination unit 89 determines that the plunger 50 has completed one reciprocating motion (i.e., one discharge operation has been performed), it outputs a reciprocating determination signal to the reciprocating count calculation unit 79 and the air entrapment detection unit 90.

[0167] The air lock detection unit 90 detects air lock when the operating mode is set to quantitative discharge mode. However, the air lock detection unit 90 may also detect air lock when the operating mode is set to continuous discharge mode. Due to various factors, gas (e.g., air or its bubbles) may enter the chamber 63. Gas may enter, for example, when attaching or detaching the cartridge. Alternatively, gas may be present in the cartridge from the beginning along with the grease.

[0168] If gas enters the chamber 63, the gas will expand and compress repeatedly as the plunger 50 moves back and forth. As a result, the check valve 64 may not open (or may not open easily) when the plunger 50 descends, and grease may not be discharged (or may not be discharged easily). Air entrapment refers to this situation, and / or the presence of gas in the chamber 63 itself, and / or the state in which the pump 60 is attempting to discharge that gas.

[0169] The air lock detection unit 90 notifies the reciprocation count calculation unit 79, the display control unit 85, the timing unit 88, and the operation control unit 91 of the air lock detection result. Specifically, the air lock detection unit 90 determines whether or not air lock has occurred each time the plunger 50 makes one reciprocation. If air lock has not occurred, it sets the air lock detection state to "not detected," and if air lock has occurred, it sets the air lock detection state to "detected." The reciprocation count calculation unit 79, the display control unit 85, the timing unit 88, and the operation control unit 91 then perform the following actions based on the set air lock detection state. This allows you to recognize whether or not air is trapped in the system.

[0170] Air entrapment can be detected based on the actual operating amount of the motor 20. The actual operating amount may be the magnitude of the fluctuation in the actual rotational speed of the motor 20, or it may be the actual rotational speed itself. More specifically, the magnitude of the fluctuation in the actual rotational speed may be, for example, the amplitude of the actual rotational speed, or it may be the derivative of the actual rotational speed.

[0171] As the plunger 50 reciprocates, a load is applied to the plunger 50 (particularly to the lower end surface of the plunger) from outside the plunger 50. Hereinafter, this load will be referred to as the "plunger load." The plunger load is applied in a direction that hinders the reciprocating motion of the plunger 50.

[0172] The plunger load is typically greater when the grease is being discharged (i.e., when the plunger 50 is moving downwards and pressing down on the grease) than when the grease is flowing into the chamber 63 (i.e., when the plunger 50 is moving upwards). Therefore, the plunger load fluctuates periodically. One cycle of fluctuation corresponds to one round trip of the plunger 50.

[0173] Fluctuations in the plunger load can be reflected in the actual rotational speed. That is, an increase in the plunger load may decrease the actual rotational speed. Conversely, a decrease in the plunger load may increase the actual rotational speed. Therefore, the actual rotational speed may change periodically, as illustrated in Figures 7 and 8. Figure 7 shows an example of the change in actual rotational speed and motor current when the pump 60 is in a normal state and the motor 20 is rotating in the low to medium speed range. Figure 8 shows an example of the change in actual rotational speed and motor current when the pump 60 is in a normal state and the motor 20 is rotating in the high speed range. The motor current is the current supplied from the drive circuit 82 to the motor 20. The normal state of the pump 60 includes a state in which no air is trapped. Note that each of the multiple "plunger one-reciprocation timings" in Figure 7 is the timing when the plunger 50 reaches a predetermined position (e.g., the highest position) in its one reciprocation. The same applies to the "plunger one-reciprocation timings" in Figures 8 and 9.

[0174] The fluctuation in actual rotational speed generally increases as the actual rotational speed increases (i.e., as the target rotational speed increases). Figure 7 illustrates the actual rotational speed when the target rotational speed is around 18,000 rpm, and as the target rotational speed increases further, the fluctuation in actual rotational speed also increases. However, in the high-speed range, the inertial force of the pump 60 increases. This inertial force acts in a direction that suppresses the decrease in actual rotational speed due to the increase in plunger load. Therefore, in the high-speed range, the fluctuation in actual rotational speed actually decreases as the actual rotational speed increases.

[0175] Furthermore, the fluctuation in plunger load when air is trapped (hereinafter abbreviated as "air trapped state") is smaller than the fluctuation in plunger load when it is in a normal state. This is because, in the air trapped state, the trapped gas is compressed when plunger 50 descends. As a result, the plunger load is smaller compared to when only the grease is being pressed.

[0176] Therefore, the fluctuation in actual rotational speed in the air-locked state is smaller than the fluctuation in actual rotational speed in the normal state. Figure 9 shows an example of changes in actual rotational speed and motor current when the motor 20 is rotating at high speed in the air-locked state. As is clear from comparing Figures 8 and 9, even if the target rotational speed is the same, both the fluctuation in actual rotational speed and the fluctuation in motor current are smaller in the air-locked state than in the normal state.

[0177] Thus, fluctuations in actual rotational speed differ depending on whether or not air is trapped in the system. Therefore, the occurrence of air trapped in the system can be detected based on fluctuations in actual rotational speed. Furthermore, it is possible to detect the occurrence of air entrapment based on the actual rotational speed itself. That is, under normal conditions, the plunger 50 is subjected to a relatively larger load compared to when air entrapment is present. Therefore, for the same target rotational speed, the actual rotational speed under normal conditions may be lower than the actual rotational speed when air entrapment is present. Thus, the occurrence of air entrapment can be detected based on the actual rotational speed.

[0178] In this way, air entrapment can be detected based on various actual operating amounts. Therefore, in this first embodiment, the air entrapment detection unit 90 determines that air entrapment has occurred based on the actual operating amount meeting predetermined requirements. The predetermined requirements may be any requirements that indicate (or make it possible to determine) that air entrapment has occurred or is likely to have occurred. In other words, the predetermined requirements may be any requirements that indicate that gas is mixed into the pump 60 (specifically, for example, the chamber 63) or is likely to be mixed in.

[0179] More specifically, the air entrapment detection unit 90 of this first embodiment determines whether or not air entrapment has occurred based on the amplitude of the actual rotational speed. As mentioned above, the actual rotational speed may fluctuate periodically during the operation of the pump 60. In other words, the amplitude of the actual rotational speed occurs during the operation of the pump 60.

[0180] Therefore, the air lock detection unit 90 detects the occurrence of air lock based on the amplitude of the actual rotational speed during a predetermined driving period. The predetermined driving period can be any period during the operation of the motor 20. In this first embodiment, the predetermined driving period is the period during which the plunger 50 completes one reciprocating motion. At each predetermined driving period (i.e., each time the plunger 50 completes one reciprocating motion), the air lock detection unit 90 determines whether or not air lock has occurred based on the amplitude of the actual rotational speed during that reciprocating motion.

[0181] The amplitude of the actual rotational speed in an air-locked state is smaller than the amplitude in a normal state. Therefore, the air-locked detection unit 90 determines that air lock has occurred when the maximum value of the amplitude within a predetermined driving period is less than or equal to the first threshold. In other words, the aforementioned predetermined requirement includes the condition that the maximum value of the amplitude within a predetermined driving period is less than or equal to the first threshold. The maximum value of the amplitude within a predetermined driving period is the difference between the maximum and minimum values ​​of the actual rotational speed within a predetermined driving period.

[0182] The first threshold may be determined to be smaller than the expected amplitude range (e.g., its minimum value) under normal conditions and larger than the expected amplitude range (e.g., its maximum value) under air entrapment conditions. The first threshold may be determined in any way.

[0183] The first threshold value may be a constant value, or it may be set variably according to the operating state of the electric lubricant dispenser 1. In this first embodiment, the first threshold value is set variably according to the operating state. In this first embodiment, the operating state includes the target rotational speed. That is, the air entrapment detection unit 90 sets a first threshold according to the current target rotational speed notified by the speed setting unit 86.

[0184] When the target rotational speed changes, the actual rotational speed also changes accordingly. When the actual rotational speed changes, the level of its amplitude also changes. In other words, the plunger load tends to increase as the actual rotational speed increases. Also, the lower the actual rotational speed, the smaller the fluctuation in the plunger load, and the more the fluctuation in the actual rotational speed is suppressed by speed feedback control. Therefore, as the actual rotational speed increases, the fluctuation in the actual rotational speed also increases. For this reason, the first threshold may be set so that it increases as the target rotational speed increases.

[0185] However, as mentioned above, in the high-speed range, the inertial force of the pump 60 increases, so the fluctuation in actual rotational speed actually decreases as the actual rotational speed increases. Therefore, the first threshold is, for example, (i) in the low to medium speed range, when the target rotational speed is high. (ii) The first threshold may be set to increase as the target rotational speed increases, and (ii) in the high-speed range, the first threshold may be set to decrease as the target rotational speed increases. More specifically, the first threshold may be set according to the target rotational speed, as illustrated in Figure 10.

[0186] The operating state may include the actual rotational speed. In other words, the first threshold may be set according to the actual rotational speed itself. In that case, the first threshold may be set in the same way as the setting method according to the target rotational speed. For example, the horizontal axis in Figure 10 may be interpreted as the actual rotational speed.

[0187] Furthermore, the operating state may include the duty cycle described above. In other words, the first threshold may be set according to the duty cycle. The first threshold may change in any way according to the duty cycle. For example, the first threshold may be set so that it increases as the duty cycle increases. Alternatively, the first threshold may be set in a manner similar to the setting method according to the target rotational speed. For example, the horizontal axis in Figure 10 may be interpreted as the duty cycle.

[0188] Furthermore, the operating state may include the equipment temperature. In other words, the first threshold may be set according to the equipment temperature. The equipment temperature is the temperature of the electric lubricant dispenser 1. Specifically, the equipment temperature may be the temperature of the grease, or a temperature that indirectly indicates the temperature of the grease.

[0189] The viscosity of the grease changes with temperature. For example, as the temperature of the grease increases, the viscosity of the grease decreases. When the viscosity of the grease decreases, the plunger load decreases, and the amplitude of the actual rotational speed decreases. For this reason, the first threshold may be set such that, for example, the first threshold decreases as the temperature of the grease increases. The air entrapment detection unit 90 receives a temperature detection signal from the temperature sensor 100 and may set the first threshold according to the temperature indicated by the temperature detection signal.

[0190] The timing unit 88 measures the duration of air lock when air lock occurs. The duration of air lock is the time during which air lock persists. Specifically, the timing unit 88 starts measuring the duration of air lock when the air lock detection state changes from "not detected" to "detected". Specifically, it accumulates (cumulatively) one count value at a time for each control cycle, and when the duration of air lock reaches a predetermined time (i.e., when the count value reaches a predetermined value), it notifies the operation control unit 91 that air lock has persisted for a predetermined time. Specifically, the timing unit 88 sets the air lock persistence state to "detected".

[0191] The reciprocating count calculation unit 79 calculates the actual number of reciprocating motions of the plunger 50 when the operating mode is the quantitative discharge mode. However, the reciprocating count calculation unit 79 may also calculate the actual number of reciprocating motions when the operating mode is the continuous discharge mode. The actual number of reciprocating motions is the actual number of times the plunger 50 has reciprocated. In other words, the actual number of reciprocating motions is the number of times the discharge operation has actually been performed. Therefore, the actual number of reciprocating motions can be rephrased as the actual number of discharges. The actual number of reciprocating motions is an example of the actual number of discharges in the summary of the embodiment.

[0192] The round trip count calculation unit 79 accumulates the actual number of round trips each time it receives a round trip determination signal from the round trip determination unit 89 (i.e., each time the plunger 50 makes one round trip). Specifically, each time the round trip count calculation unit 79 receives a round trip determination signal, it updates the actual number of round trips to a value that is "1" higher than the current value.

[0193] However, the round trip count calculation unit 79 does not update the actual round trip count while air entrapment is detected by the air entrapment detection unit 90 (i.e., while the air entrapment detection state is set to "detected"). In other words, it temporarily stops accumulating the actual round trip count. Then, once the air entrapment is resolved, the air entrapment... When the detection status is set to "Not Detected," the accumulation of the actual round trip count resumes from the value at the time of the pause.

[0194] The round-trip count calculation unit 79 notifies the display control unit 85 of the current actual number of round trips. Furthermore, the round-trip count calculation unit 79 outputs the round-trip count difference to the operation control unit 91. The round-trip count difference is the difference between the target number of round trips and the current actual number of round trips.

[0195] In continuous discharge mode, the operation control unit 91 commands the motor drive control unit 92 to drive the motor 20 while the trigger switch 8 is ON. Specifically, the operation control unit 91 outputs a drive command to the motor drive control unit 92 and notifies it of the current target rotational speed. The drive command requests that the motor 20 be driven.

[0196] In quantitative dispensing mode, the motion control unit 91 commands the motor drive control unit 92 to drive the motor 20 while the trigger switch 8 is ON. Specifically, the motion control unit 91 outputs a drive command to the motor drive control unit 92 and notifies it of the current target rotational speed. When the reciprocating count difference notified by the reciprocating count calculation unit 79 reaches zero, the motion control unit 91 stops outputting the drive command and stops the motor 20.

[0197] When operating in quantitative discharge mode, if the timing unit 88 detects a continuous air lock condition (i.e., if air lock occurs for a predetermined period of time), the operation control unit 91 stops the output of the drive command and stops the motor 20, even if the trigger switch 8 is ON and the difference in the number of reciprocating cycles has not yet reached zero.

[0198] The motor drive control unit 92 calculates the rotational position (specifically the electrical angle) and actual rotational speed of the motor 20 based on the first to third rotational signals from the first to third rotational position sensors 28A to 28C.

[0199] The motor drive control unit 92 performs speed feedback control when it receives a drive command and a target rotational speed from the motion control unit 91. Specifically, the motor drive control unit 92 calculates the speed deviation, which is the difference between the target rotational speed and the actual rotational speed. The motor drive control unit 92 then calculates the duty cycle required to make the speed deviation zero (i.e., to make the actual rotational speed match the target rotational speed). It then outputs a drive control signal to each of the two target switches to turn on. The target switches are two of the first to sixth switches Q1 to Q6, corresponding to the rotational position. At least one of the drive control signals to the target switches is a pulse width modulated signal with the calculated duty cycle. Therefore, the higher the duty cycle, the greater the power supplied to the motor 20.

[0200] The display control unit 85 displays the rotation speed level input from the operation mode setting unit 87 on the first display screen 74. The display control unit 85 displays the actual number of reciprocations input from the reciprocation count calculation unit 79 on the set reciprocation count display screen 75. The display control unit 85 executes notification processing when it is notified that air lock has occurred. The notification processing notifies the user that air lock has occurred. The notification processing may be performed in any way. The notification processing may be performed in a way that allows the user to visually and / or audibly recognize that air lock has occurred. In the first embodiment, air lock is notified by flashing the second display screen 75A and the third display screen 75B. Alternatively, the display control unit 85 may notify air lock by displaying a preset number, symbol, character, etc. on the second display screen 75A and the third display screen 75B. The display control unit 85 is an example of a notification unit in the summary of the embodiment.

[0201] (2-1-6) Main Processing To realize various functions in quantitative dispensing mode, the control circuit 80 (more details on the CPU) The main processing performed by 80A) will be explained with reference to Figure 11. When the control circuit 80 is set to quantitative dispensing mode, it performs the main processing shown in Figure 11.

[0202] When the control circuit 80 starts the main process, it determines in S110 whether the trigger switch 8 is ON or OFF. If the trigger switch 8 is OFF, the process proceeds to S120. In S120, the control circuit 80 executes the stop-down process. Details of the stop-down process are shown in Figure 12.

[0203] When the control circuit 80 transitions to the stop processing, it stops the motor 20 in S210. Specifically, the motion control unit 91 stops outputting the drive command. In S220, the control circuit 80 determines whether the current round-trip count difference is zero. If the round-trip count difference is not zero, the process proceeds to S240. In this case, the current round-trip count difference is maintained. If the round-trip count difference is zero, the process proceeds to S230. An example of a case where the round-trip count difference is zero in S220 may include the case where the motor 20 is automatically stopped after the target number of round trips of the plunger 50 are completed, and the user then turns off the trigger 9. In S230, the control circuit 80 resets the actual number of round trips to an initial value (e.g., zero).

[0204] In S240, the control circuit 80 determines whether or not a change operation has been performed to modify the target number of round trips. The change operation includes turning on the second switch 72 or the third switch 73. If no change operation has been performed, the process proceeds to S270. If a change operation has been performed, the process proceeds to S250.

[0205] In S250, the control circuit 80 resets the actual number of round trips to its initial value. In S260, the control circuit 80 changes the target number of round trips according to the change operation. In S270, the control circuit 80 determines whether a speed change operation has been performed. The speed change operation includes turning on the first switch 71. If no speed change operation has been performed, the process proceeds to S290. If a speed change operation has been performed, the process proceeds to S280. In S280, the control circuit 80 changes the rotation speed level (i.e., changes the maximum rotation speed) in accordance with the speed change operation.

[0206] In S290, the control circuit 80 sets the air lock persistence state to "not detected". The control circuit 80 further sets (resets) the air lock persistence time to zero. After processing in S290, the process proceeds to S140 (Figure 11).

[0207] If the trigger switch 8 is turned on in S110, the process proceeds to S130. In S130, the control circuit 80 executes the in-operation processing. Details of the in-operation processing are shown in Figure 13.

[0208] When the control circuit 80 transitions to the operation process, in S310 it determines whether the air lock-in state is set to "detected". If the air lock-in state is not set to "detected", the process proceeds to S320. In S320, the control circuit 80 determines whether the current round-trip count difference is greater than 0. If the round-trip count difference is 0, the control circuit 80 stops driving the motor 20 in S410, similar to S210. A round-trip count difference of 0 corresponds to the discharge operation having been performed for the target number of round trips. After S410, the process proceeds to S420.

[0209] In S320, if the difference in the number of round trips is greater than 0, the process proceeds to S330. A difference in the number of round trips being greater than 0 corresponds to the fact that the actual number of round trips has not yet reached the target number of round trips. In S330, the control circuit 80 drives the motor 20 at a target rotational speed corresponding to the current rotational speed level. That is, it performs the speed feedback control described above.

[0210] In S340, the control circuit 80 determines whether the plunger 50 has completed one round trip. In S350, the control circuit 80 executes an air lock detection process. The air lock detection process is a process to detect whether or not an air lock has occurred. Details of the air lock detection process are shown in Figure 14.

[0211] When the control circuit 80 moves to the air entrapment detection process, it calculates the actual rotational speed of the motor 20 in S510. In S520, the control circuit 80 updates the maximum or minimum value of the actual rotational speed. The maximum and minimum values ​​of the actual rotational speed are (i) reset each time the plunger 50 completes one reciprocating motion, and (ii) updated each time S520 is executed after the reset.

[0212] For example, if the latest actual rotational speed calculated in S510 is greater than the currently held maximum value, the maximum actual rotational speed is updated to that latest actual rotational speed. Also, for example, if the latest actual rotational speed is less than the currently held minimum value, the minimum actual rotational speed is updated to that latest actual rotational speed. Also, for example, if the latest actual rotational speed is greater than or equal to the currently held minimum value and less than or equal to the maximum value, the current maximum and minimum values ​​are maintained.

[0213] In S530, the control circuit 80 determines whether the plunger 50 has completed one reciprocal motion based on the determination result in S340. If the plunger 50 has not yet completed one reciprocal motion, the process proceeds to S540. In S540, the control circuit 80 maintains the current air entrapment detection state ("detected" or "not detected"). After processing in S540, the process proceeds to S360 (Figure 13).

[0214] In S530, if the plunger 50 completes one round trip, the process proceeds to S550. In S550, the control circuit 80 sets the first threshold. Specifically, as described above, the control circuit 80 sets the first threshold based on the target rotational speed, duty cycle, actual rotational speed, or equipment temperature.

[0215] In S560, the control circuit 80 determines whether the maximum amplitude of the actual rotational speed is greater than the first threshold. The maximum amplitude is the difference between the maximum and minimum values ​​of the currently held actual rotational speed. For each cycle of the plunger 50, S520 obtains the maximum and minimum values ​​of the actual rotational speed during that cycle. The difference between these maximum and minimum values ​​is the maximum amplitude.

[0216] If the maximum amplitude is greater than the first threshold, the process proceeds to S570. In this case, the control circuit 80 determines that no air lock has occurred. Therefore, in S570, the control circuit 80 sets the air lock detection state to "not detected". After processing in S570, the process proceeds to S590.

[0217] If the maximum amplitude is less than or equal to the first threshold, the process proceeds to S580. In this case, the control circuit 80 determines that air lock has occurred. Therefore, in S580, the control circuit 80 sets the air lock detection state to "detected". After processing in S580, the process proceeds to S590.

[0218] In S590, the control circuit 80 resets the currently held maximum and minimum values ​​of the actual rotational speed. The control circuit 80 further resets the determination result in S340 that the plunger 50 has completed one reciprocation, and restarts the determination of whether or not the plunger 50 has completed one reciprocation. Therefore, when the plunger 50 completes one reciprocation from the timing of this restart, the determination of one reciprocation of the plunger 50 is made again in S340. After processing in S590, this process moves on to S360 (Figure 13).

[0219] In S360, the control circuit 80 determines whether the plunger 50 has completed one round trip based on the determination result in S340. If the plunger 50 has not completed one round trip, the process proceeds to S420. If the plunger 50 has completed one round trip, the process proceeds to S370.

[0220] In S370, the control circuit 80 determines whether the air lock detection state is set to "detected". If the air lock detection state is set to "detected", that is, if air lock has occurred, the process proceeds to S400. In S400, the control circuit 80 starts the notification process described above. That is, it notifies the user that air lock has occurred. After the processing in S400, the process proceeds to S420.

[0221] In S370, if the air lock detection status is not set to "detected," that is, if no air lock has occurred, the process proceeds to S380. In S380, the control circuit 80 increments the actual round trip count. That is, it adds "1" to the current actual round trip count. In S390, if the notification process is being executed, the control circuit 80 terminates that notification process. After the processing in S390, the process proceeds to S420.

[0222] Furthermore, if the air lock detection status in S370 is set to "Detected," the actual number of reciprocations is not incremented, and the current actual number of reciprocations is maintained. In other words, as long as air lock is detected, the actual number of reciprocations does not change even if the plunger 50 makes one reciprocation.

[0223] If the air lock condition is set to "detected" in S310, the process proceeds to S430. In S430, the control circuit 80 stops the motor 20 from running, similar to S210. After the process in S430, the process proceeds to S140 (Figure 11).

[0224] In S420, the control circuit 80 executes a continuation determination process. Details of the continuation determination process are shown in Figure 15. When the control circuit 80 moves to the continuation determination process, in S610 it determines whether the air lock detection state is set to "detected". If the air lock detection state is not set to "detected", that is, if no air lock has occurred, this process moves to S620.

[0225] In S620, the control circuit 80 resets the air-entry duration to zero. After processing in S620, the process proceeds to S140 (Figure 11). In S610, if the air lock detection state is set to "detected," that is, if air lock has occurred, the process proceeds to S630. In S630, the control circuit 80 accumulates the duration of the air lock. In other words, it accumulates (cumulatively) one of the aforementioned count values ​​used for measurement.

[0226] In S640, the control circuit 80 determines whether the duration of air lock is greater than or equal to a predetermined time (i.e., the count value is greater than or equal to a predetermined value). If the duration of air lock is less than the predetermined time, the process proceeds to S140 (Figure 11). If the duration of air lock is greater than or equal to the predetermined time, the process proceeds to S650.

[0227] In S650, the control circuit 80 sets the air lock-in state to "detected". In other words, it determines that the air lock-in has been occurring for a predetermined time or longer. After S650, this process proceeds to S140 (Figure 11).

[0228] In S140, the control circuit 80 calculates (i.e., updates) the round-trip count difference. Specifically, it subtracts the current actual round-trip count from the current target round-trip count. Then, it updates the round-trip count difference to the result of that subtraction.

[0229] In S150, the control circuit 80 determines whether the current actual number of reciprocations is zero. If the actual number of reciprocations is not zero, the process proceeds to S160. In this case, the plunger 50 has already made at least one reciprocation in quantitative dispensing mode. Therefore, in S160, the control circuit 80 displays the current actual number of reciprocations on the set count display screen 75. This allows the user to recognize how far the grease has been dispensed. After processing in S160, the process proceeds to S110.

[0230] If the actual number of round trips is zero in S150, the process proceeds to S170. In this case, for example, it is possible that trigger 9 has not yet been manually operated, or that trigger 9 has been manually operated but the actual number of round trips has not yet reached one. Therefore, in S170, the control circuit 80 displays the target number of round trips on the set count display screen 75. This allows the user to recognize the target number of round trips. After the processing in S160, the process proceeds to S110.

[0231] Here, we will briefly explain the correspondence between the processes in Figures 11 to 15 and Figure 6. S110, S310, and S320 correspond to the processes performed by the motion control unit 91. S210, S330, S410, and S430 correspond to the processes performed by the motion control unit 91 and the motor drive control unit 92. S140, S220, S230, S250, and S380 correspond to the processes performed by the round-trip count calculation unit 79. S240 and S260 correspond to the processes performed by the round-trip count setting unit 83. S270 and S280 correspond to the processes performed by the operation mode setting unit 87. S290 and S420 correspond to the processes performed by the timing unit 88. S340 and S360 correspond to the processes performed by the round-trip determination unit 89. S350 corresponds to the processes performed by the air entrapment detection unit 90. S370 corresponds to the processes performed by the round-trip count calculation unit 79 and the display control unit 85. S150-S170, S390, and S400 correspond to processing by the display control unit 85.

[0232] [2-2. Second Embodiment] Another example of the air-entry detection process will be described as a second embodiment. The electric lubricant dispenser of this second embodiment is basically configured the same as the electric lubricant dispenser 1 of the first embodiment, except for the air-entry detection process. The configuration that differs from the first embodiment will be described below.

[0233] In this second embodiment, the air entrapment detection unit 90 detects the occurrence of air entrapment based on the derivative of the actual rotational speed. The derivative may be calculated in any way. For example, the derivative may be calculated based on the time derivative. That is, the amount of change in the actual rotational speed per predetermined unit time may be calculated as the derivative. Alternatively, for example, the derivative may be calculated based on the rotational angle derivative. That is, the amount of change in the actual rotational speed while the motor 20 (more specifically the rotor 22) rotates by a predetermined unit rotational angle may be calculated as the derivative.

[0234] In an air-locked state, fluctuations in the actual rotational speed are relatively small. Small fluctuations in the actual rotational speed correspond to small absolute values ​​of its derivative. Therefore, air lock can be detected based on the absolute value (maximum value) of the derivative within a predetermined operating period. For example, if the maximum value of the absolute value of the derivative is less than or equal to a second threshold, it may be determined that air lock has occurred.

[0235] However, the difference in plunger load due to the presence or absence of air entrapment is particularly noticeable when plunger 50 is descending (i.e., during discharge operation). If no gas is present when plunger 50 descends, plunger 50 will be subjected to a relatively large load, and its actual rotational speed may decrease significantly. In other words, a large deceleration may occur.

[0236] On the other hand, if gas is mixed in when plunger 50 descends, the plunger load becomes relatively smaller, and therefore the degree of decrease in actual rotational speed is also relatively small. In other words, the deceleration is relatively small.

[0237] Therefore, in this second embodiment, air entrapment is detected by focusing particularly on deceleration (i.e., the absolute value of the derivative of the actual rotational speed when the plunger descends). Specifically, it is determined that air entrapment has occurred when the maximum value of the deceleration is less than or equal to the second threshold. In other words, the aforementioned predetermined requirement in this second embodiment includes the condition that the maximum value of the deceleration within a predetermined driving period is less than or equal to the second threshold.

[0238] The second threshold may be determined to be smaller than the expected deceleration range under normal conditions (e.g., its minimum value) and larger than the expected deceleration range under air entrapment conditions (e.g., its maximum value). The second threshold may be determined in any way.

[0239] The second threshold value may be a constant value, but in this second embodiment, similar to the first threshold value in the first embodiment, it is variably set according to the operating state of the electric lubricant dispenser 1. Specifically, the second threshold value may be set according to the target rotational speed. More specifically, the second threshold value may be set according to the target rotational speed in the same manner as the first threshold value. That is, in the speed range from low speed to medium speed, the second threshold value may be set to increase as the target rotational speed increases, and in the high-speed range, the second threshold value may be set to decrease as the target rotational speed increases. For example, the vertical axis in FIG. 10 may be read as the second threshold value.

[0240] Also, for example, the second threshold value may be set according to various operating states such as the actual rotational speed, duty ratio, or device temperature, in the same manner as the first threshold value. Specifically, the second threshold value may be set according to the actual rotational speed in the same manner as the setting method according to the target rotational speed. For example, the horizontal axis in FIG. 10 may be read as the actual rotational speed and the vertical axis may be read as the second threshold value. Also, the second threshold value may be set according to the duty ratio in the same manner as the setting method of the first threshold value according to the duty ratio. For example, the horizontal axis in FIG. 10 may be read as the duty and the vertical axis may be read as the second threshold value. Also, the second threshold value may be set based on the device temperature in the same manner as the setting method of the first threshold value based on the device temperature. Specifically, the second threshold value may be set so as to decrease as the temperature of the grease increases.

[0241] To realize such detection of air biting, in the second embodiment, in S350 of FIG. 13, instead of the air biting detection process of FIG. 14, the air biting detection process shown in FIG. 16 is executed.

[0242] The air biting detection process of FIG. 16 is different from the air biting detection process of FIG. 14 in that (i) S521 is executed instead of S520, (ii) S551 is executed instead of S550, (iii) S561 is executed instead of S560, and (iv) S591 is executed instead of S590.

[0243] In S521, the control circuit 80 calculates the differential value of the actual rotational speed calculated in S510. The control circuit 80 further updates the maximum value of the deceleration based on the calculated differential value. The maximum value of the deceleration can be (i) reset each time the plunger 50 makes one reciprocation and (ii) updated each time S521 is executed after the reset. For example, if the latest differential value calculated in S521 is a negative value and the absolute value of the differential value (i.e., the deceleration) is greater than the currently held maximum value of the deceleration, the maximum value of the deceleration is updated to the latest deceleration.

[0244] In S551, the control circuit 80 sets a second threshold value. Specifically, as described above, the control circuit 80 sets the second threshold value based on, for example, the target rotational speed, the duty ratio, the actual rotational speed, or the device temperature.

[0245] In S561, the control circuit 80 determines whether the currently held maximum value of the deceleration is greater than the second threshold value. If the maximum value of the deceleration is greater than the second threshold value, this process proceeds to S570. In this case, the control circuit 80 determines that no air biting has occurred. If the maximum value of the deceleration is less than or equal to the second threshold value, this process proceeds to S580. In this case, the control circuit 80 determines that air biting has occurred. When the maximum value is less than or equal to the second threshold value, this process proceeds to S580. In this case, the control circuit 80 determines that air biting has occurred.

[0246] In S591, the control circuit 80 resets the currently held maximum value of the deceleration. The control circuit 80 further resets the determination result of S340 indicating that the plunger 50 has made one reciprocation, similar to S590 of the first embodiment, and newly restarts the determination of whether the plunger 50 has made one reciprocation.

[0247] [2-3. Third Embodiment] A further example of the air biting detection process will be described as the third embodiment. The electric lubricant feeder of this third embodiment is basically configured in the same manner as the electric lubricant feeder 1 of the first embodiment, except for the air biting detection process. Hereinafter, the configuration different from the first embodiment will be described.

[0248] In this third embodiment, the air lock detection unit 90 detects the occurrence of air lock based on the actual rotational speed itself. As described above, for the same target rotational speed, the actual rotational speed in a normal state may be lower than the actual rotational speed in an air lock state. Therefore, in this third embodiment, it is determined that air lock has occurred when the minimum value of the actual rotational speed within a predetermined drive period is equal to or greater than the third threshold. In other words, the aforementioned predetermined requirement in this third embodiment includes the condition that the minimum value of the actual rotational speed within a predetermined drive period is equal to or greater than the third threshold.

[0249] The third threshold value may be a constant value, but in this third embodiment, like the first and second threshold values, it is variably set according to the operating state of the electric lubricant dispenser 1. Specifically, the third threshold may be set according to the target rotational speed. More specifically, the third threshold may be set to a value smaller than the target rotational speed. For example, each time the target rotational speed is changed, the third threshold may be set by a predetermined calculation based on the changed target rotational speed. The predetermined calculation may be configured, for example, to set the third threshold to be lower than the target rotational speed by a predetermined speed or predetermined percentage. The predetermined speed or predetermined percentage may be changed according to the target rotational speed. In addition, the third threshold may be variably set based on the actual rotational speed or duty cycle. Specifically, the third threshold is basically set based on the target rotational speed, and in addition, may be adjusted (i.e., changed) based on the actual rotational speed or duty cycle.

[0250] Furthermore, the third threshold may be varied according to the equipment temperature. For example, while it is based on being set according to the target rotational speed, the third threshold may be set so that it increases as the equipment temperature rises.

[0251] To achieve this type of air lock detection, in this third embodiment, at S350 in Figure 13, the air lock detection process shown in Figure 17 is executed instead of the air lock detection process shown in Figure 14.

[0252] The air-entry detection process in Figure 17 differs from the air-entry detection process in Figure 14 in that (i) S522 is executed instead of S520, (ii) S552 is executed instead of S550, (iii) S562 is executed instead of S560, and (iv) S592 is executed instead of S590.

[0253] In S522, the control circuit 80 updates the minimum value of the actual rotational speed based on the actual rotational speed calculated in S510. The minimum value of the actual rotational speed is (i) reset each time the plunger 50 completes one cycle, and (ii) updated each time S522 is executed after the reset. For example, if the latest actual rotational speed calculated in S510 is smaller than the currently held minimum value. The minimum actual rotational speed is updated to the most recent actual rotational speed.

[0254] In S552, the control circuit 80 sets a third threshold. Specifically, as described above, the control circuit 80 sets the third threshold based on various operating conditions, such as the target rotational speed or the equipment temperature.

[0255] In S562, the control circuit 80 determines whether the currently held minimum actual rotational speed is less than the third threshold. If the minimum actual rotational speed is less than the third threshold, the process proceeds to S570. In this case, the control circuit 80 determines that no air has entered the system. If the minimum actual rotational speed is greater than or equal to the third threshold, the process proceeds to S580. In this case, the control circuit 80 determines that air has entered the system.

[0256] In S592, the control circuit 80 resets the currently held minimum value of the actual rotational speed. Furthermore, similar to S590 in the first embodiment, the control circuit 80 resets the determination result in S340 that the plunger 50 has completed one reciprocation, and restarts the determination of whether or not the plunger 50 has completed one reciprocation.

[0257] [2-4. Other Embodiments] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0258] (2-4-1) In the above embodiment, air entrapment was detected based on the amplitude of the actual rotational speed, the derivative of the actual rotational speed, or the actual rotational speed itself. However, air entrapment may be detected based on any actual operating quantity that indicates the actual rotational speed or the magnitude of its fluctuations.

[0259] (2-4-2) The operating conditions referenced in setting the first threshold are not limited to the operating conditions exemplified in each of the above embodiments (target rotational speed, duty cycle, actual rotational speed, or equipment temperature). The first threshold may be set based on any operating condition in the electric lubricant dispenser 1. The operating condition may be any that affects the actual rotational speed, that is, any condition in which the actual rotational speed may change in response to a change in the operating condition.

[0260] For example, the operating state may be the battery voltage. In other words, the first threshold may be set according to the magnitude of the battery voltage. Even if the duty cycle is constant, if the battery voltage decreases, the power supplied to the motor 20 will also decrease, and the actual rotational speed will decrease as a result. For this reason, the first threshold may be set according to the magnitude of the battery voltage. Specifically, the first threshold may be set so that it decreases as the battery voltage decreases. To achieve this, the electric lubricant dispenser 1 may be equipped with a voltage detector that detects the battery voltage. The voltage detector may be configured to (i) receive the battery voltage and (ii) output a voltage detection signal to the control circuit 80 according to the magnitude of that voltage. The control circuit 80 may (i) acquire the magnitude of the battery voltage based on the voltage detection signal from the voltage detector and (ii) set the first threshold based on the acquired magnitude.

[0261] The second and third thresholds may also be set variably based on various other operating conditions. (2-4-3) In the first embodiment, the first threshold value may be set based on the average value of a numerical value indicating the operating state (hereinafter referred to as the "state quantity"). The average value is, in other words, a smoothed value. Examples of the state quantity include the target rotation speed, the duty ratio, the actual rotation speed, or the device temperature. The average value of the state quantity may be calculated by any method. For example, the interval average value or the moving average value of the state quantity may be calculated. In this case, the first threshold value may be set according to the calculated interval average value or the moving average value. The calculation target interval of the interval average value and the moving average value may be determined in any way. The calculation target interval may be, for example, the aforementioned predetermined driving period (that is, the period during which the plunger 50 makes a reciprocating motion).

[0262] Alternatively, a low-pass filter for inputting the state quantity may be provided. The low-pass filter removes components with a frequency of a predetermined value or higher from the state quantity input in a time series and outputs the state quantity from which the components have been removed. The first threshold value may be set according to the output value of the low-pass filter. The low-pass filter may be realized by the CPU 80A executing the program of the low-pass filter.

[0263] Regarding the second threshold value of the second embodiment and the third threshold value of the third embodiment, similarly to the first threshold value, they may be set based on the averaged state quantity. (2-4-4) In the above embodiment, as the predetermined processing executed when air biting is detected, notification processing and a temporary stop of the integration of the actual reciprocating number are exemplified. However, when air biting is detected, other predetermined processing may be executed in addition to or instead of these processings.

[0264] (2-4-5) In the above embodiment, the reciprocating determination unit 89 determined one reciprocating motion of the plunger 50 based on the first to third rotation signals. However, one reciprocating motion of the plunger 50 may be determined by any method. For example, a sensor capable of detecting the rotation of the crankshaft 46 may be provided near the crankshaft 46. One reciprocating motion of the plunger 50 may be determined based on the detection result from that sensor. Alternatively, for example, a sensor that detects the position of the plunger 50 or slider 48 may be provided near the plunger 50 or slider 48. One reciprocating motion of the plunger 50 may be determined based on the detection result from that sensor.

[0265] (2-4-6) The technology of the present disclosure is applicable to all types of reciprocating pumps. For example, the present disclosure is applicable to diaphragm pumps. Furthermore, it is applicable not only to reciprocating pumps but to all types of pumps capable of discharging lubricants.

[0266] (2-4-7) The electric lubricant dispenser 1 may be configured to dispense lubricants other than grease. These lubricants may be, for example, semi-solid or liquid (e.g., lubricating oil).

[0267] (2-4-8) The rotation speed level, operating mode, and target number of reciprocations may be set in a manner different from that of the above embodiment. For example, a user interface (e.g., a button, dial, lever, touch panel, etc.) of a different form than the second and third switches 72 and 73 of the above embodiment may be provided for setting the operating mode. The operating mode may be switched in response to the operation of the user interface. The same applies to the target number of reciprocations. The rotation speed level may also be switched in response to the operation of a user interface (e.g., a button, dial, lever, touch panel, etc.) of a different form than the first switch 71 of the above embodiment.

[0268] (2-4-9) In the above embodiment, the rotational state of the motor 20 (i.e., rotational position and actual rotational speed) was obtained using the first to third rotational position sensors 28A to 28C. However, the rotational state may be obtained by other means. For example, so-called sensorless control may be employed in the electric lubricant dispenser 1. That is, the rotational state of the motor may be obtained based on the induced voltage generated in each of the three coils 24 of the motor 20.

[0269] [2-5. Supplementary Information] The multiple functions achieved by one component in the above embodiment may be achieved by multiple components, and the single function achieved by one component may be achieved by multiple components. This may be achieved by the components. Furthermore, multiple functions achieved by multiple components may be achieved by one component, and one function achieved by multiple components may be achieved by one component. Also, some of the components of the above embodiment may be omitted. Furthermore, at least some of the components of one embodiment may be added to or replaced by the components of another embodiment. [Explanation of Symbols]

[0270] 1...Electric lubricant dispenser, 8...Trigger switch, 9...Trigger, 15...Battery pack, 20...Motor, 28A~28C...1st~3rd rotational position sensors, 48...Slider, 50...Plunger, 60...Pump, 63...Chamber, 66A...Discharge port, 70...Operation panel, 80...Control circuit, 80A...CPU, 80B...Semiconductor memory, 82...Drive circuit.

Claims

1. Motor and, A pump driven by the aforementioned motor and configured to discharge lubricant, A drive circuit configured to drive the motor, A control circuit, The drive circuit is controlled to rotate the motor, During the operation of the motor, if the actual operating amount, which indicates the actual rotational speed of the motor or the magnitude of fluctuations in the actual rotational speed, satisfies a predetermined requirement indicating that gas is mixed into the pump, a predetermined process is performed. A control circuit configured as follows, An electric lubricant dispenser equipped with the following features.

2. An electric lubricant dispenser according to claim 1, The actual operating amount includes the amplitude of the actual rotational speed. The aforementioned predetermined requirement includes the condition that the maximum value of the amplitude within a predetermined driving period is less than or equal to a first threshold, Electric lubricant dispenser.

3. An electric lubricant dispenser according to claim 1 or claim 2, The actual operating amount includes the absolute value of the derivative of the actual rotational speed. The aforementioned predetermined requirement includes the condition that the maximum value of the absolute value within the predetermined driving period is less than or equal to the second threshold. Electric lubricant dispenser.

4. An electric lubricant dispenser according to any one of claims 1 to 3, The actual operating amount includes the actual rotational speed, The aforementioned predetermined requirement includes the condition that the minimum value of the actual rotational speed within a predetermined driving period is equal to or greater than the third threshold. Electric lubricant dispenser.

5. An electric lubricant dispenser according to claim 2, The control circuit is configured to change the first threshold value according to the operating state of the electric lubricant dispenser. Electric lubricant dispenser.

6. An electric lubricant dispenser according to claim 3, The control circuit is configured to change the second threshold value according to the operating state of the electric lubricant dispenser. Electric lubricant dispenser.

7. An electric lubricant dispenser according to claim 4, The control circuit is configured to change the third threshold value according to the operating state of the electric lubricant dispenser. Electric lubricant dispenser.

8. An electric lubricant dispenser according to any one of claims 5 to 7, The control circuit is configured to (i) set a target rotational speed which is a target value for the rotational speed of the motor, and (ii) control the drive circuit so that the actual rotational speed matches the target rotational speed. The aforementioned operating state includes the aforementioned target rotational speed, Electric lubricant dispenser.

9. An electric lubricant dispenser according to any one of claims 5 to 7, The control circuit is configured to control the drive circuit by outputting a pulse-width modulated signal having a duty cycle to the drive circuit. The drive circuit is configured to receive the pulse width modulated signal and drive the motor according to the received pulse width modulated signal. The aforementioned operating state includes the duty cycle, Electric lubricant dispenser.

10. An electric lubricant dispenser according to any one of claims 5 to 7, The aforementioned operating state includes the aforementioned actual rotational speed, Electric lubricant dispenser.

11. An electric lubricant dispenser according to any one of claims 5 to 7, The control circuit is configured to acquire the temperature of the electric lubricant dispenser, The aforementioned operating state includes the temperature, Electric lubricant dispenser.

12. An electric lubricant dispenser according to any one of claims 1 to 11, The pump is equipped with a notification unit configured to notify information indicating that the gas is mixed in with the pump, The predetermined process includes broadcasting the information via the notification unit. Electric lubricant dispenser.

13. An electric lubricant dispenser according to any one of claims 1 to 12, The pump is configured to repeatedly perform a predetermined discharge operation for discharging the lubricant, The aforementioned control circuit is While the motor is running, each time the pump performs the predetermined discharge operation, the actual number of discharges, which is the number of times the predetermined discharge operation has been performed, is accumulated. The motor is stopped based on the fact that the actual number of discharges has reached the target number of discharges. It is configured in such a way, The predetermined process includes temporarily suspending the accumulation of the actual number of discharges, Electric lubricant dispenser.

14. An electric lubricant dispenser according to claim 13, The control circuit is configured to temporarily stop accumulating the actual number of discharges, and then resume accumulating the actual number of discharges based on the fact that the actual operating amount no longer meets the predetermined requirements. Electric lubricant dispenser.

15. An electric lubricant dispenser according to any one of claims 1 to 14, The aforementioned pump, A chamber configured to contain the aforementioned lubricant, A discharge port communicating with the aforementioned chamber, (i) A plunger located within the chamber, and (ii) configured to reciprocate within the chamber by the motor to discharge the lubricant within the chamber from the discharge port, It is equipped with Electric lubricant dispenser.

16. An electric lubricant dispenser according to any one of claims 2 to 11, The aforementioned pump, A chamber configured to contain the aforementioned lubricant, A discharge port communicating with the aforementioned chamber, (i) A plunger located within the chamber, and (ii) configured to reciprocate within the chamber by the motor to discharge the lubricant within the chamber from the discharge port, Equipped with, The predetermined driving period includes the period during which the plunger makes one round trip within the chamber. Electric lubricant dispenser.

17. An electric lubricant dispenser according to claim 13 or claim 14, The aforementioned pump, A chamber configured to contain the aforementioned lubricant, A discharge port communicating with the aforementioned chamber, (i) A plunger located within the chamber, and (ii) configured to reciprocate within the chamber by the motor to discharge the lubricant within the chamber from the discharge port, Equipped with, The predetermined discharge operation includes the plunger making one round trip within the chamber. Electric lubricant dispenser.

18. An electric lubricant dispenser according to any one of claims 1 to 17, The control circuit is configured to stop the motor when the actual operating amount has remained in a state that satisfies the predetermined requirements for a predetermined period of time while the motor is being driven. Electric lubricant dispenser.

19. An electric lubricant dispenser according to any one of claims 1 to 18, The control circuit is configured to detect, in response to the fulfillment of the predetermined requirements while the motor is being driven, that the gas is mixed into the pump and / or that the pump is about to discharge the gas. Electric lubricant dispenser.

20. A method for dispensing lubricant from an electric lubricant dispenser, The pump of the electric lubricant dispenser, which is configured to discharge the lubricant, is driven by the motor of the electric lubricant dispenser. During the operation of the motor, the electric lubricant dispenser performs a predetermined process based on the fact that the actual operating amount, which indicates the actual rotational speed of the motor or the magnitude of fluctuations in the actual rotational speed, satisfies a predetermined requirement indicating that gas is mixed into the pump. A method that includes [the following features].

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