Vibration isolator for a power tool circuit board

Abstract

Power tool, comprising: a housing having a motor housing portion, a front housing portion coupled to the motor housing portion, and a handle portion extending from the motor housing portion; a motor held in the motor housing portion; an output driven by the motor to rotate about an axis, the output extending from the front housing portion; an actuator held by the handle portion and configured to control operation of the motor; a printed circuit board held in a receiving area between the actuating element and the front housing section; and a vibration isolator located on the circuit board and between the circuit board and the housing.

Description

Technical area

[0001] The present disclosure relates to a power tool having a circuit board. background

[0002] Power tools often generate vibrations during operation. Power tools also typically contain electrical and electronic components, such as circuit boards, which can be damaged or shortened by vibrations. Overview

[0003] There is a need for a solution to protect the circuit board of a power tool from vibration without significantly increasing the size of the power tool.

[0004] In some aspects, the techniques described herein relate to a power tool comprising: a housing having a motor housing portion, a front housing portion coupled to the motor housing portion, and a handle portion extending from the motor housing portion; a motor carried in the motor housing portion; an output driven by the motor and rotating about an axis, the output extending from the front housing portion; an actuator carried by the handle portion and configured to control operation of the motor; a circuit board carried in a receiving area between the actuator and the front housing portion; and a vibration isolator disposed on the circuit board and between the circuit board and the housing.

[0005] In some aspects, the techniques described herein relate to a power tool, wherein the vibration isolator is configured to reduce the transmission of vibrations generated by operation of the power tool to the circuit board.

[0006] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is made from a foam material.

[0007] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is compressed between the circuit board and the housing.

[0008] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is bonded to the circuit board.

[0009] In some aspects, the techniques described herein relate to a power tool in which the circuit board includes a plurality of semiconductor switching elements.

[0010] In some aspects, the techniques described herein relate to a power tool in which the circuit board extends parallel to the axis.

[0011] In some aspects, the techniques described herein relate to a power tool in which the actuating member is a trigger that can be moved in a direction parallel to the axis to change the operating speed of the motor.

[0012] In some aspects, the techniques described herein relate to a power tool wherein the housing comprises cooperating shell halves defining the motor housing portion and the handle portion, the shell halves defining a top wall of the receiving area, the top wall extending adjacent a bottom surface of the front housing portion, and the vibration isolator is compressed between the circuit board and the top wall.

[0013] In some aspects, the techniques described herein relate to a power tool comprising: a housing having a motor housing portion, a front housing portion coupled to the motor housing portion, and a handle portion extending from the motor housing portion; a motor supported within the motor housing portion; an impact mechanism driven by the motor to transmit rotary impacts to an output extending from the front housing portion, the output rotatable about an axis; an actuator supported by the handle portion and configured to control operation of the motor; a circuit board extending parallel to the axis, the circuit board supported within the housing and having a first side facing the impact mechanism and a second side facing the actuator; and a vibration isolator disposed on the first side of the circuit board.

[0014] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is configured to reduce the transmission of vibrations generated by operation of the power tool to the circuit board.

[0015] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is made from a foam material.

[0016] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator is compressed between the first side of the circuit board and the housing.

[0017] In some aspects, the techniques described herein relate to a power tool in which the circuit board is held in a receiving area between the front housing portion and the actuator.

[0018] In some aspects, the techniques described herein relate to a power tool wherein the housing comprises cooperating shell halves defining the motor housing portion and the handle portion, the shell halves defining a top wall of the receiving area, the top wall extending adjacent a bottom surface of the front housing portion, and the vibration isolator is compressed between the first side of the circuit board and the top wall.

[0019] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator covers less than 50% of the first side of the circuit board.

[0020] In some aspects, the techniques described herein relate to a power tool comprising: a housing having cooperating shell halves defining a motor housing portion and a handle portion extending from the motor housing portion, the housing further comprising a front housing portion coupled to the shell halves; a motor carried in the motor housing portion; an output driven by the motor to rotate about an axis, the output extending from the front housing portion; an actuator carried by the handle portion and configured to control operation of the motor;a circuit board held in a receiving area between the actuator and the front housing portion, the shell halves defining a top wall of the receiving area, the top wall extending adjacent a bottom surface of the front housing portion; and a vibration isolator disposed between the circuit board and the top wall.

[0021] In some aspects, the techniques described herein relate to a power tool in which the actuating element is a multi-position switch.

[0022] In some aspects, the techniques described herein relate to a power tool in which the vibration isolator comprises a foam material compressed between the circuit board and the top wall.

[0023] In some aspects, the techniques described herein relate to a power tool in which the actuating member is a trigger configured to control the operating speed of the motor. Short description of the drawings Fig. 1 shows a perspective view of a power tool. Fig. 2 shows a cropped perspective view of the power tool from Fig. 1. Fig. 3 shows a sectional view of the power tool from Fig. 1 along line 3-3. Fig. 4 shows a perspective close-up of a circuit board of the power tool from Fig. 1.

[0024] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure may be implemented and practiced otherwise. It is also to be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered limiting. Detailed description

[0025] Fig. 1 shows an embodiment of a power tool in the form of a rotary impact tool, more specifically an impact wrench 10. The impact wrench 10 consists of a housing 14 with a motor housing portion 18, an impact housing or front housing portion 22 coupled to the motor housing portion 18, and a handle portion 26 extending downwardly from the motor housing portion 18. In the embodiment shown, the handle portion 26 and the motor housing portion 18 are defined by cooperating first and second shell halves or housing portions 28a, 28b; however, in other embodiments, the housing 14 may also be constructed differently.

[0026] As in Fig. 1, the shell halves 28A, 28B are coupled (e.g., attached) at an interface or seam 32. The illustrated housing 14 also includes an end cap 30 coupled to the motor housing portion 18 opposite the front housing portion 22. In other embodiments, the impact wrench 10 may not have a separate end cap, so that the shell halves 28a, 28b instead define the rear end of the motor housing portion 18. In other embodiments, the front housing portion 22 may be omitted or enclosed by the shell halves 28a, 28b.

[0027] The illustrated impact wrench 10 includes a battery 36 releasably coupled to a battery receptacle 38 in the handle portion 26. A motor 42 is housed in the motor housing portion 18 and receives power from the battery 36 via connections, pads, and / or battery terminals in the battery receptacle 38 when the battery 36 is coupled to the battery receptacle 38. In the illustrated embodiment, the handle portion 26 of the shell halves 28a, 28b may be covered or surrounded by a grip portion 44, which may be molded onto the handle portion 26.

[0028] The battery 36 may be a rechargeable battery used primarily for operating a power tool, such as an electric drill, an electric saw, or the like (e.g., a 12-volt rechargeable battery). The battery 36 may comprise lithium-ion (Li-ion) cells. The 12-volt nominal voltage of the battery 36 provides an optimal weight / size-to-power ratio in the illustrated impact wrench 10; however, batteries with other nominal voltages may also be used in other embodiments.

[0029] With reference to Fig. 2-3 of the illustrated embodiment, the motor 42 is located within the motor housing portion 18 adjacent the end cap 30. The illustrated motor 42 is a brushless direct current ("BLDC") motor having a stator and a rotor or output shaft 54 ​​extending through the stator and rotatable about a rotational axis A1 relative to the stator. In other embodiments, the motor 42 may be a different type of motor, such as a brushed motor, an external rotor motor, and the like.

[0030] A gear assembly 46, which is held by the motor housing section 18, receives the torque from the output shaft 54 ​​of the motor 42 and provides a speed reduction between the output shaft 54 ​​and a striking mechanism 50 ( Fig. 3). The illustrated gear assembly 46 consists of a pinion 56 coupled to the output shaft 54 ​​of the motor 42, a plurality of planetary gears 58 meshing with the pinion 56, and a ring gear 62 meshing with the planetary gears 58 and non-rotatably fixed in the motor housing section 18. The planetary gears 58 are coupled to a camshaft 66 of the striking mechanism 50, so that the camshaft 66 serves as a planetary carrier. The illustrated ring gear 62 is held directly by the shell halves 28A, 28B; however, the ring gear 62 may also be held in another manner (for example, in a gear housing).

[0031] The impact mechanism 50 is configured to convert the constant rotational force or torque of the motor 42 and the gear assembly 46 into an impacting rotational force or intermittent torque. The illustrated impact mechanism 50 includes the camshaft 66, a hammer 70, a spring 74, and an anvil 78. The camshaft 66 is configured to transmit the rotational motion from the planetary gears 58 to the hammer 70 and includes cam grooves 82 in which corresponding cam balls 86 are received. The hammer 70 is configured to reciprocate axially along the camshaft 66 and, in response to the rotation of the camshaft 66, to impart periodic rotational shocks to the anvil 78. The spring 74 biases the hammer 70 axially toward the anvil 78 along the rotational axis A1. The anvil 78 protrudes from the front housing section 22 and defines an output of the impact wrench 10, which is rotatable about the axis A1.The anvil 78 shown has a distal end or drive to which a tool element (e.g., a socket, not shown) can be coupled to perform work on a workpiece (e.g., a fastener).

[0032] With reference to Fig. 2 and Fig. 3, the impact wrench 10 further includes a trigger 90, a multi-position switch 94, a first circuit board 98, and a second circuit board 102. The trigger 90 and the multi-position switch 94, which may also be referred to as actuators, are supported by the handle portion 26 of the housing 14 and are configured to control the operating characteristics of the motor 42 based on user inputs. In particular, the trigger 90 can be moved by the user along a trigger axis A2 parallel to the rotational axis A1 to turn the motor on and off and, in some embodiments, to control the speed of the motor 42 (e.g., proportional to the movement of the trigger 90 along the trigger axis A2).The multi-position switch 94 can be moved by a user into a variety of positions along the multi-position switch axis A3, which is orthogonal to the rotation axis A1 and the trigger axis A2, to control the desired direction of rotation of the motor 42.

[0033] In the illustrated embodiment, the first circuit board 98 is located within the motor housing section 18 adjacent the front end of the motor 42. The illustrated first circuit board 98 extends perpendicular to the rotational axis A1 and includes one or more Hall-effect sensors that provide feedback for controlling the motor 42. In some embodiments, the first circuit board 98 may be omitted, and the motor 42 may be configured for sensorless control via the second circuit board 102.

[0034] With reference to Fig. 3, the second circuit board 102 extends parallel to the rotation axis A1 and is arranged in a receiving area 101 between an upper end of the handle portion 26 and a bottom surface of the front housing portion 22 (and between the trigger 90 and the front housing portion 22 in the illustrated embodiment). In the illustrated embodiment, the circuit board 102 is held in a plurality of recesses 106 formed on the inside of the two shell halves 28A, 28B. The recesses 106 hold the second circuit board 102 and limit the movement of the second circuit board 102 in a direction parallel to the rotation axis A1. The second circuit board 102 is in electrical connection with the motor 42, the trigger 90, and the terminals (not shown) of the battery receptacle 38.In the embodiment shown, the second circuit board 102 includes a plurality of semiconductor switching elements (e.g., MOSFETs, IGBTs, and the like), one or more microprocessors, machine-readable non-volatile memory elements, and other electrical or electronic elements for controlling the operation of the impact wrench 10. In addition, the second circuit board 102 may be at least partially encapsulated with an encapsulating material (e.g., transparent epoxy polymer) applied to selected areas or selected electrical or electronic elements.

[0035] As in Fig.4, the second circuit board 102 also has a first side 108 facing the striking mechanism 50 and a second side 112 facing the multi-position switch 94. The vibration isolator 116 is located on the first side 108 of the second circuit board 102. The illustrated vibration isolator 116 is made of a non-conductive elastomer (e.g., foam material, rubber, or silicone) and is adhesively bonded to the first side 108. The vibration isolator 116 fills a gap between the first side 108 of the second circuit board 102 and a top wall 111 of the receiving area 101, which, in the illustrated embodiment, extends adjacent to the underside of the front housing section 22. In some embodiments, the vibration isolator 116 may be compressed between the top wall 111 and the second circuit board 102 such that the vibration isolator 116 biases the second circuit board 102 toward the multi-position switch 94.

[0036] In operation, the cam balls 86 are in driving engagement with the hammer 70, and when the hammer 70 and anvil 78 are engaged, the movement of the cam balls 86 in the cam grooves 82 allows relative axial movement of the hammer 70 along the camshaft 66 as the hammer 70 and anvil 78 engage and the camshaft 66 continues to rotate. The axial movement of the hammer 70 compresses the spring 74, which, upon retraction of the hammer 70 a sufficient distance from the anvil 78, releases its stored energy to drive the hammer 70 forward and rotate it. The hammer 70 then strikes the anvil 78 to transmit torque to the anvil 78, and the process repeats.

[0037] The elastic properties of the vibration isolator reduce the transmission of vibrations in an axis orthogonal to the rotational axis A1 generated by the impact mechanism 50 during operation of the impact wrench 10. The pressure exerted by the vibration isolator 116 on the second circuit board 102 can also reduce oscillations of the circuit board 102 that may be caused by such vibrations. By subjecting the second circuit board 102 to fewer vibrations, the service life of the impact wrench 10 can be extended. In the illustrated embodiment, the vibration isolator 116 covers less than 50% of the total surface area of ​​the second circuit board 102 and is attached only to the first side 108. In other embodiments, the vibration isolator 116 may cover a larger portion of the second circuit board 102 and be attached directly to the electrical or electronic elements of the second circuit board 102.In other embodiments, both the first and second sides 108, 112 or only the second side 112 may include vibration isolators 116 attached to the second circuit board 102 and in contact with a portion of the housing 14.

[0038] Various features and aspects of the present disclosure are set forth in the following claims.

Claims

[1] Power tool comprising: a housing having a motor housing portion, a front housing portion coupled to the motor housing portion, and a handle portion extending from the motor housing portion; a motor held in the motor housing portion; an output driven by the motor to rotate about an axis, the output extending from the front housing portion; an actuator held by the handle portion and configured to control operation of the motor; a printed circuit board held in a receiving area between the actuating element and the front housing section; and a vibration isolator located on the circuit board and between the circuit board and the housing. [2] A power tool according to claim 1, wherein the vibration isolator is arranged to reduce the transmission of vibrations generated by operation of the power tool to the circuit board. [3] Power tool according to claim 1 or 2, wherein the vibration isolator consists of a foam material. [4] A power tool according to any preceding claim, wherein the vibration isolator is compressed between the circuit board and the housing. [5] Power tool according to one of the preceding claims, wherein the vibration isolator is glued to the circuit board. [6] Power tool according to one of the preceding claims, wherein the circuit board comprises a plurality of semiconductor switching elements. [7] Power tool according to one of the preceding claims, wherein the circuit board extends parallel to the axis. [8] A power tool according to any preceding claim, wherein the actuating member is a trigger movable in a direction parallel to the axis to vary the operating speed of the motor. [9] A power tool according to any preceding claim, wherein the housing comprises cooperating shell halves defining the motor housing portion and the handle portion, the shell halves defining a top wall of the receiving area, the top wall extending adjacent a bottom surface of the front housing portion, and the vibration isolator being compressed between the circuit board and the top wall. [10] Power tool comprising: a housing having a motor housing portion, a front housing portion coupled to the motor housing portion, and a handle portion extending from the motor housing portion; a motor held in the motor housing portion; a percussion mechanism driven by the motor to transmit rotational impacts to an output extending from the front housing portion, the output being rotatable about an axis; an actuator held by the handle portion and configured to control operation of the motor; a circuit board extending parallel to the axis, the circuit board being held in the housing and having a first side facing the striking mechanism and a second side facing the actuating element; and a vibration isolator mounted on the first side of the circuit board. [11] A power tool according to claim 10, wherein the vibration isolator is arranged to reduce the transmission of vibrations generated by operation of the power tool to the circuit board. [12] Power tool according to claim 10 or 11, wherein the vibration isolator consists of a foam material. [13] A power tool according to any one of claims 10 to 12, wherein the vibration isolator is compressed between the first side of the circuit board and the housing. [14] Power tool according to one of claims 10-13, wherein the circuit board is held in a receiving area between the front housing section and the actuating element. [15] The power tool of claim 14, wherein the housing comprises cooperating shell halves defining the motor housing portion and the handle portion, the shell halves defining a top wall of the receiving area, the top wall extending adjacent a bottom surface of the front housing portion, and the vibration isolator being compressed between the first side of the circuit board and the top wall. [16] A power tool according to any one of claims 10-15, wherein the vibration isolator covers less than 50% of the first side of the circuit board. [17] Power tool comprising: a housing having cooperating shell halves defining a motor housing portion and a handle portion extending from the motor housing portion, the housing further comprising a front housing portion coupled to the shell halves; a motor held in the motor housing portion; an output driven by the motor to rotate about an axis, the output projecting from the front housing portion; an actuator held by the handle portion and configured to control operation of the motor; a circuit board held in a receiving area between the actuator and the front housing portion, the shell halves defining a top wall of the receiving area extending adjacent a bottom of the front portion of the housing; and a vibration isolator located between the circuit board and the top wall. [18] Power tool according to claim 17, wherein the actuating element is a multi-position switch. [19] A power tool according to claim 17 or 18, wherein the vibration isolator comprises a foam material compressed between the circuit board and the top wall. [20] A power tool according to any one of claims 17 to 19, wherein the actuating element is a trigger arranged to control the operating speed of the motor.

Images