JPWO2020254281A5

JPWO2020254281A5 -

Info

Publication number: JPWO2020254281A5
Application number: JP2021574863A
Authority: JP
Publication date: 2023-06-20

Claims

a housing (10);
an input shaft (20);
an output shaft (15);
A two-speed transmission adapted to be disposed within a power tool, comprising:
The 2nd speed transmission provides torque to and through the planetary gear (18) in high torque/low speed drive mode or past the planetary gear (18) in low torque/high speed drive mode. a torque responsive gearshift mechanism (19) for directing the
said planet gear (18) comprises a sun gear (21) connected to said input shaft (20), a ring gear (22) fixed to said housing (10) and a planet carrier (24);
The gear shift mechanism (19) comprises a drive member (26) connected to the sun gear (21) of the planetary gear (18), a driven member (27) connected to the output shaft (15), and a second so that at one position the drive member (26) and the driven member (27) are mutually coupled and at a second position the planet carrier (24) and the driven member (27) are mutually coupled. a plurality of coupling elements (30) arranged,
The driven member (27) is arranged to support the coupling element (30) for axially displacing the coupling element (30) between the first position and the second position. a plurality of axially extending grooves (36) arranged in the
said drive member (26) comprises axially acting first cam means (35) for cooperating with said coupling element (30) in said first position of said coupling element (30);
A first axially acting spring means (31) is arranged for biasing said coupling element (30) towards said first position of said coupling element (30), whereby The action of said first spring means (31) counteracts the axial force exerted by said coupling element (30) by said first cam means (35), said coupling element (30) being at a predetermined level It is maintained in said first position at the following torque values, but is pushed out from said first position by said first cam means (35) at torque values above said predetermined level,
Said driven member (27) is provided in said axially extending groove (36) and is adapted to allow said spring to move when said coupling element (30) leaves said first position at a torque value above said predetermined level. a second axially acting, arranged to exert an axially displacing force on said coupling element (30) towards said second position against the biasing action of means (31); further comprising a cam means (36b);
Said planet carrier (24) supports said coupling element (30) only radially in said second position of said coupling element (30) and said coupling element (30) in said second position of said coupling element (30). coupled to a coupling sleeve (29) comprising a plurality of axially extending tracks (38) for cooperating with the element (30);
Said drive member comprises a plurality of recesses (39), each of said first axially acting cam elements (35) respectively forming part of one of said recesses and each of said recesses is adapted to receive and radially support one of said coupling elements (30) in said first position of said coupling element (30) and in said high speed/low torque mode said coupling element (30) is disconnected from said coupling sleeve to be rotationally decoupled;
A two-speed power transmission device for an electric tool, characterized by:

the coupling sleeve is arranged to be axially movable,
A two-speed power transmission device for a power tool according to claim 1.

further comprising axially acting second spring means (40) for biasing said axially movable coupling sleeve (29) against said coupling element (30);
A two-speed power transmission device for a power tool according to claim 2.

Said planet carrier (24) comprises an outer sleeve (32) extending axially to hold said planet carrier (24) and said driven member (27) in said second position. rotatably locked to said coupling sleeve (29) for mutual coupling;
A two-speed power transmission device for an electric power tool according to any one of claims 1 to 3.

A first axial bearing (33) is provided to support the drive member to the planet carrier and a second axial bearing (34) to support the outer sleeve to the housing (10). ) so that forces from said first spring means acting on said coupling member can be absorbed by said housing through said first and second bearings;
A two-speed power transmission device for a power tool according to claim 4.

said coupling elements (30) are composed of balls (30) of the same size,
A two-speed power transmission device for an electric power tool according to any one of claims 1 to 5.

the number of tracks (38) of the coupling sleeve is twice the number of coupling elements (30);
A two-speed power transmission device for an electric power tool according to any one of claims 1 to 6.

said drive member (26) comprises an axial flange (26b), said axial flange (26b) arranged to radially support said coupling element;
A two-speed power transmission device for an electric power tool according to any one of claims 1 to 7.

the axial extent of the flange plus the depth of the recess is greater than the radius of the ball (30);
A two-speed transmission for a power tool as claimed in claim 8 when dependent on claim 7.

said first spring means (31) comprises a first coil spring (31) arranged coaxially with said driven member (27) and providing a biasing force on said ball (30);
A two-speed power transmission device for an electric power tool according to any one of claims 1 to 9.

A power tool comprising: a two-speed power transmission device according to any one of claims 1 to 10; a motor; means for monitoring a quantity indicative of torque supplied from said tool; a control unit operable to control the rotational speed of the motor based on the sensed quantity.

12. The method of claim 11, wherein said means for monitoring a quantity indicative of torque supplied by said tool comprises at least one of a torque transducer (sensor) and a circuit arrangement adapted to monitor motor current. Power tools as described.

13. A method of controlling a power tool according to claim 12, comprising the steps of: a.
monitoring a quantity indicative of the first torque value;
comparing the first torque value to a predetermined threshold torque value;
controlling the rotational speed of the motor when the measured value approaches the threshold;
including
The method wherein controlling the rotational speed of the motor includes reducing the rotational speed of the motor when the measured value approaches the threshold.

14. The method of claim 13, wherein the quantity is at least one of a motor current and a torque transducer value.