GB2583796A - Motor terminals facing gear case in a power tool - Google Patents

Motor terminals facing gear case in a power tool Download PDF

Info

Publication number
GB2583796A
GB2583796A GB1916565.3A GB201916565A GB2583796A GB 2583796 A GB2583796 A GB 2583796A GB 201916565 A GB201916565 A GB 201916565A GB 2583796 A GB2583796 A GB 2583796A
Authority
GB
United Kingdom
Prior art keywords
motor
terminals
power tool
gear case
shows
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1916565.3A
Other versions
GB201916565D0 (en
Inventor
F Nace Daniel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Black and Decker Inc
Original Assignee
Black and Decker Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Black and Decker Inc filed Critical Black and Decker Inc
Priority to GB1916565.3A priority Critical patent/GB2583796A/en
Publication of GB201916565D0 publication Critical patent/GB201916565D0/en
Publication of GB2583796A publication Critical patent/GB2583796A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/22—Auxiliary parts of casings not covered by groups H02K5/06-H02K5/20, e.g. shaped to form connection boxes or terminal boxes
    • H02K5/225—Terminal boxes or connection arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/46—Fastening of windings on the stator or rotor structure
    • H02K3/52—Fastening salient pole windings or connections thereto
    • H02K3/521—Fastening salient pole windings or connections thereto applicable to stators only
    • H02K3/522—Fastening salient pole windings or connections thereto applicable to stators only for generally annular cores with salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans
    • H02K7/145—Hand-held machine tool
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Motor Or Generator Frames (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)

Abstract

A power tool which comprises an elongated handle including a motor housing and a handle portion, and a gear house disposed at a front end of the motor housing. A power module is provided within the elongated handle. An electric motor is provided within the motor housing, the motor including a plurality of terminals, the terminals being positioned proximate the gear case. The power tool may be an angle grinder. By placing the electrical connections adjacent the gearbox, they may be more shielded from external contamination drawn in with the motor cooling air, reducing metal contamination and abrasion and tracking or electrical shorting between the terminals. Having the terminals at the opposite end to the power module may allow for easier encapsulation of the terminals by means of dipping.

Description

Motor Terminals Facing Gear Case in a Power Tool The present invention relates to a power tool such as an angle grinder. Typically, in such power tools, a gear case is provided that includes the transmission gear, and an elongated handle is provided rearward of the gear case that includes a motor housing, a handle portion, and a power receptacle. A motor is disposed in a motor housing with motor terminals facing the handle portion. The handle portion in many designs includes power and/or control modules that regulate supply of electric power to the motor. A series of power lines are routed from the power module to the motor terminals.
Power tools such as small angle grinders (SAGs) are vulnerable to metal contamination abrasion and tracking (electrical shorting) due to their applications and environments. This contamination is "ingested" into the tool with the air flow required for cooling and creates reliability issues from abrasion and tracking due to its abrasiveness and conductivity. Brushless motors in such power tools are especially susceptible because they require wire routing along the end of the stator to connect the numerous coils and the have additional lead wires for addition phases vs a typical universal motor. Accordingly, all termination points & wire connections must be fully insulated/sealed to prevent contamination ingress & tracking against the exposed wires. In some designs, layers of shrink tube and/or epoxy are applied over all exposed metal. This is a very timely and costly process and has a high risk for exposed metal that could lead to failure.
Additionally, since the wire routing and termination points are on the upstream end of the motor, the contamination has a tendency to build up on the flat surfaces and restricted areas due to the large connections. These large connections also impede airflow in a critical area where we must maintain a small girth (gripping surface) and also house the rear bearing and sense system.
Accordingly, there is provided a power tool according to claim 1.
Two embodiments of the present invention will now be described with reference to the accompanying drawings of which: Figurel shows a side view of a known design of a power tool such as an angle grinder including a motor with terminals facing the handle portion; Figure 2 shows an axial view of the end of the motor of Figure 1 facing the handle portion; Figure 3 shows perspective view of a motor including shrink tubes around the terminals to prevent tracking to the stator lamination stack; Figure 4 shows a side view of a power tool with motor terminals placed in front of the motor proximate the gear case; Figure 5 shows an axial view of the front of the motor of Figure 4 facing the gear case; Figure 6 shows a perspective view of the motor including a motor terminal according to a first embodiment; Figure 7 shows a side view of the motor with the motor terminal of Figure 6; Figure 8 shows a perspective view of the motor including a motor terminal according to a second embodiment; Figure 9 shows a side view of the motor with the motor terminal of Figure 8; Figure 10 shows a perspective view of the motor including a motor terminal according to a third embodiment; Figure 11 shows a side view of the motor with the motor terminal of Figure 10; Figure 12 shows a perspective view of the power tool showing the rear of the motor housing; and Figure 13 shows a perspective view of the power tool showing the front of the motor housing.
These figures are described here in detail.
Figurel shows a side view of a known design of a power tool such as an angle grinder including a motor with terminals facing the handle portion. Figure 2 shows an axial view of the end of the motor of Figure 1 facing the handle portion.
Figure 3 shows perspective view of a motor including shrink tubes around the terminals to prevent tracking to the stator lamination stack. For the reasons discussed above, this arrangement encounters problems with airflow restriction, tracking risk, and difficulty in insulation protection.
Figure 4 shows a side view of a power tool with motor terminals placed in front of the motor proximate the gear case. Figure 5 shows an axial view of the front of the motor of Figure 4 facing the gear case. The mating area between the motor housing and the gear case in most angle grinders has a larger diameter to allow for disposition of the motor fan and/or baffle. This area has access clearance that is not needed for airflow and typically walled off with ribs. In an embodiment, to avoid the problems discussed above related to airflow restriction, tracking risk, and difficulty in insulation protection, the lead wires are terminated proximate the mating area between the motor housing and the gear case. In an embodiment, the stator terminals allow the lead wire to attach in a way that allows the existing lead wire to be routed past or along the stator lamination stack.
Figure 6 shows a perspective view of the motor including a motor terminal according to a first embodiment. Figure 7 shows a side view of the motor with the motor terminal of Figure 6. In this embodiment, the terminals are provided with radially-outward projecting portions that receive the ends of lead wires therein. Specifically, each terminal includes a planar portion that is received within a receiving pocket of the stator end insulator and a radially projecting portion that extends from the planar portion approximately perpendicularly. The lead wires exit the front of the stator facing the gear case, are routed along the outer surface of the stator lamination stack, and are connected to the power module within the handle portion. The end insulators of the stator may be provided with wire traps to route the lead wires.
Figure 8 shows a perspective view of the motor including a motor terminal according to a second embodiment. Figure 9 shows a side view of the motor with the motor terminal of Figure 8. In this embodiment, the terminals are axially arranged. Specifically, each terminal includes a planar portion that is received within a receiving pocket of the stator end insulator and a lead wire receiving portion that extends from the planar portion approximately axially. The wires are clamped within the wire reiving portion, run along the terminal, and are routed along the outer surface of the stator lamination stack.
Figure 10 shows a perspective view of the motor including a motor terminal according to a third embodiment. Figure 11 shows a side view of the motor with the motor terminal of Figure 10. In this embodiment, the motor terminal includes a main radially-oriented portion that is attached to the stator lamination stack, and a wire receiving portion that extends axially from the main portion to receive the end of the lead wire.
Having the exposed connections on the front of the stator without the lead wires reward allow for the stator to be dipped, covering all critical areas with tracking/abrasion protection in one application. The manufacturing method would significantly reduce steps & cost. Further, no terminals are provided in areas where contamination builds and is forced into openings. As shown in Figure 12, wire cross section is much smaller than the terminal tower, support structure and double layer of shrink tube, resulting in lower airflow restriction. Also, as shown in Figure 13, the front of the stator has extra space which could house additional ribbing to better protect/ close off the electrical connections.

Claims (1)

  1. Claims: 1. A power tool comprising: an elongated handle including a motor housing and a handle portion; a gear house disposed at a front end of the motor housing; an electric motor provided within the motor housing, the motor including a plurality of terminals; and a power module provided within the elongated handle, characterized in that the plurality of terminals are provided proximate the gear case.
GB1916565.3A 2019-11-15 2019-11-15 Motor terminals facing gear case in a power tool Withdrawn GB2583796A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1916565.3A GB2583796A (en) 2019-11-15 2019-11-15 Motor terminals facing gear case in a power tool

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1916565.3A GB2583796A (en) 2019-11-15 2019-11-15 Motor terminals facing gear case in a power tool

Publications (2)

Publication Number Publication Date
GB201916565D0 GB201916565D0 (en) 2020-01-01
GB2583796A true GB2583796A (en) 2020-11-11

Family

ID=69063266

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1916565.3A Withdrawn GB2583796A (en) 2019-11-15 2019-11-15 Motor terminals facing gear case in a power tool

Country Status (1)

Country Link
GB (1) GB2583796A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150364972A1 (en) * 2013-04-04 2015-12-17 Makita Corporation Angle tool and electric tool
WO2016192003A1 (en) * 2015-06-01 2016-12-08 Ac (Macao Commercial Offshore) Limited Brushless can motor
EP3187309A1 (en) * 2014-08-29 2017-07-05 Hitachi Koki Co., Ltd. Electric working machine
US20190280560A1 (en) * 2015-02-04 2019-09-12 Makita Corporation Power tool

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150364972A1 (en) * 2013-04-04 2015-12-17 Makita Corporation Angle tool and electric tool
EP3187309A1 (en) * 2014-08-29 2017-07-05 Hitachi Koki Co., Ltd. Electric working machine
US20190280560A1 (en) * 2015-02-04 2019-09-12 Makita Corporation Power tool
WO2016192003A1 (en) * 2015-06-01 2016-12-08 Ac (Macao Commercial Offshore) Limited Brushless can motor

Also Published As

Publication number Publication date
GB201916565D0 (en) 2020-01-01

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)