U.S. patent number 8,584,770 [Application Number 12/729,867] was granted by the patent office on 2013-11-19 for spindle bearing arrangement for a power tool.
This patent grant is currently assigned to Black & Decker Inc.. The grantee listed for this patent is Sankarshan Murthy, James T. Rill, David C. Tomayko, Qiang Zhang. Invention is credited to Sankarshan Murthy, James T. Rill, David C. Tomayko, Qiang Zhang.
United States Patent |
8,584,770 |
Zhang , et al. |
November 19, 2013 |
Spindle bearing arrangement for a power tool
Abstract
A power tool with a motor, a housing, a transmission, an output
spindle, a front bearing and a rear bearing. The motor has an
output shaft. The transmission is disposed in the housing and
receives a rotary input from the output shaft. The transmission
includes an input planetary stage, which has an input planet
carrier, and an output planetary stage. The output spindle is
driven by the transmission and has a first end, which extends at
least partly through the input planetary stage, and a second end
opposite the first end. The front bearing is disposed between the
output spindle and the housing to support the second end of the
output spindle for rotation about the spindle axis. The rear
bearing indirectly supports the first end of the output spindle in
the housing for rotation about the spindle axis.
Inventors: |
Zhang; Qiang (Lutherville,
MD), Tomayko; David C. (Ellicott City, MD), Murthy;
Sankarshan (Cockeysville, MD), Rill; James T.
(Hampstead, MD) |
Applicant: |
Name |
City |
State |
Country |
Type |
Zhang; Qiang
Tomayko; David C.
Murthy; Sankarshan
Rill; James T. |
Lutherville
Ellicott City
Cockeysville
Hampstead |
MD
MD
MD
MD |
US
US
US
US |
|
|
Assignee: |
Black & Decker Inc.
(Newark, DE)
|
Family
ID: |
44008166 |
Appl.
No.: |
12/729,867 |
Filed: |
March 23, 2010 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20110232930 A1 |
Sep 29, 2011 |
|
Current U.S.
Class: |
173/178;
173/216 |
Current CPC
Class: |
B25B
21/00 (20130101); B23Q 5/04 (20130101); B25B
21/02 (20130101); B25F 5/001 (20130101) |
Current International
Class: |
B23Q
5/00 (20060101); E21B 19/16 (20060101); E21B
17/22 (20060101); E21B 3/00 (20060101); E21B
19/18 (20060101) |
Field of
Search: |
;173/5,39-41,140,178
;474/53-54 ;475/331 |
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Primary Examiner: Long; Robert
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Claims
What is claimed is:
1. A power tool comprising: a motor having an output shaft; a
housing; a transmission in the housing and receiving a rotary input
from the output shaft, the transmission comprising a planet
carrier; an output spindle driven by the transmission, the output
spindle comprising a first end, which is supported for rotation
about the spindle longitudinal axis by the planet carrier, and a
second end opposite the first end, the second end extending from
the housing and being adapted to drive a chuck into which a tool
bit is removably received; a first bearing engaging the housing and
the planet carrier, the first bearing supporting the planet carrier
for rotation about the spindle axis; and a second bearing engaging
the housing and the output spindle, the second bearing being
configured to support the output spindle for rotation about the
spindle longitudinal axis at a location nearer to the second end
than the first end of the output spindle.
2. The power tool of claim 1, wherein the output shaft is received
in the first end of the output spindle.
3. The power tool of claim 1, wherein a diameter of the first end
is smaller than a diameter of a portion of the output shaft engaged
by the first bearing.
4. The power tool of claim 1, further comprising a torque clutch
that can cooperate with the transmission to limit an output torque
of the power tool.
5. The power tool of claim 4, wherein the transmission further
comprises a ring gear and wherein the torque clutch comprises a
follower member that is biased into engagement with the ring gear
to resist rotation of the ring gear relative to the housing.
6. The power tool of claim 4, wherein the torque clutch is disposed
between the first and second ends of the output spindle.
7. The power tool of claim 1, wherein a spindle lock is mounted to
the output spindle between the first and second ends.
8. The power tool of claim 7, wherein the spindle lock is mounted
to a portion of the output spindle having a diameter that is
different than a diameter of the first end and a diameter of the
second end.
9. The power tool of claim 1, wherein the transmission comprises an
output planetary stage and another planetary stage that is disposed
between the motor and the output planetary stage, the planet
carrier being associated with the another planetary stage.
10. The power tool of claim 1, wherein the transmission is a single
speed transmission.
11. The power tool of claim 1, wherein the transmission includes a
member that is movable between a first position and a second
position, wherein the transmission operates in a first speed ratio
to transmit rotary power when the member is in the first position,
and wherein the transmission operates in a second, different speed
ratio to transmit rotary power when the member is in the second
position.
12. The power tool of claim 11, wherein the member is movable along
a longitudinal axis of the transmission.
13. The power tool of claim 12, wherein the member is non-rotatably
engaged to the first bearing when the member is in the first
position.
14. The power tool of claim 13, wherein the member is a ring
gear.
15. A power tool comprising: a motor having an output shaft; a
housing; a transmission in the housing and receiving a rotary input
from the output shaft, the transmission comprising a planet
carrier; a chuck; an output spindle driven by the transmission, the
output spindle comprising a first end, which is supported for
rotation about the spindle longitudinal axis by the planet carrier,
and a second end opposite the first end, the second end being
mounted to the chuck; a first bearing engaging the housing and the
planet carrier, the first bearing supporting the planet carrier for
rotation about the spindle axis; and a second bearing engaging the
housing and the output spindle, the second bearing being configured
to support the output spindle for rotation about the spindle
longitudinal axis at a location nearer to the second end than the
first end of the output spindle; wherein the transmission includes
a member that is movable between a first position and a second
position, wherein the transmission operates in a first speed ratio
to transmit rotary power when the member is in the first position,
and wherein the transmission operates in a second, different speed
ratio to transmit rotary power when the member is in the second
position; wherein the member is movable along a longitudinal axis
of the transmission; wherein the member is non-rotatably engaged to
the first bearing when the member is in the first position; and
wherein the first bearing comprises a first set of teeth and
wherein the member comprises a second set of teeth that are
engageable to the first set of teeth.
16. The power tool of claim 12, wherein the movable member is
disposed between the first and second ends of the output
spindle.
17. A power tool comprising: a motor having an output shaft; a
housing; a transmission in the housing and receiving a rotary input
from the output shaft, the transmission comprising an input stage
and a planet carrier; a chuck; an output spindle driven by the
transmission, the output spindle having a first end, which extends
at least partly through the input stage, and a second end opposite
the first end, the second end directly driving the chuck, the
output spindle consisting of a single, continuous shaft member that
extends between and includes the first and second ends; a front
bearing that engages the output spindle and the housing to support
the second end of the output spindle for rotation about the spindle
longitudinal axis; and a rear bearing received in the housing and
supporting an element of the transmission for rotation in the
housing, the element of the transmission receiving the first end of
the output spindle therein such that the rear bearing indirectly
supports the first end of the output spindle in the housing for
rotation about the spindle longitudinal axis.
18. The power tool of claim 17, wherein the first end of the output
spindle is journally received into an element of the
transmission.
19. The power tool of claim 17, wherein the element of the
transmission comprises at least one of the planet carrier and a sun
gear.
20. The power tool of claim 17, wherein a spindle lock is mounted
to the output spindle between the first and second ends.
Description
FIELD
The present disclosure relates to a spindle bearing arrangement for
a power tool.
BACKGROUND
U.S. Pat. No. 6,431,289 and U.S. patent application Ser. No.
12/610,762 disclose various rotary power tools having an output
spindle, which is driven by a planetary-type transmission, and a
torque limiting clutch for selectively limiting an output torque of
the rotary power tool. While such rotary power tools are
satisfactory for their intended purposes, such rotary power tools
are nonetheless susceptible to improvement.
SUMMARY
This section provides a general summary of the disclosure, and is
not a comprehensive disclosure of its full scope or all of its
features.
In one form, the teachings of the present disclosure provide a
power tool having a motor, a housing, a transmission, an output
spindle, a first bearing and a second bearing. The motor has an
output shaft. The transmission is at least partly disposed in the
housing and receives a rotary input from the output shaft. The
transmission includes a planet carrier. The output spindle is
driven by the transmission and includes a first end, which is
supported for rotation about a spindle axis by the planet carrier,
and a second end opposite the first end. The first bearing is
disposed between the housing and the planet carrier and supports
the planet carrier for rotation about the spindle axis. The second
bearing is disposed between the housing and the output spindle and
is configured to support the output spindle for rotation about the
spindle axis at a location proximate the second end.
In another form, the teachings of the present disclosure provide a
power tool with a motor, a housing, a transmission, an output
spindle, a front bearing and a rear bearing. The motor has an
output shaft. The transmission is disposed in the housing and
receives a rotary input from the output shaft. The transmission
includes an input planetary stage, which has an input planet
carrier, and an output planetary stage. The output spindle is
driven by the transmission and has a first end, which extends at
least partly through the input planetary stage, and a second end
opposite the first end. The front bearing is disposed between the
output spindle and the housing to support the second end of the
output spindle for rotation about the spindle axis. The rear
bearing indirectly supports the first end of the output spindle in
the housing for rotation about the spindle axis.
In still another form, the present disclosure provides a power tool
that includes a motor, a housing, a transmission, an output
spindle, a spindle lock and front and rear bearings. The motor has
an output shaft. The transmission is disposed in the housing and
receives a rotary input from the output shaft. The transmission
includes an input planetary stage, which has an input planet
carrier, and an output planetary stage. The output spindle is
driven by the transmission and is received through the output
planetary stage such that the first end extends at least partly
through the input planetary stage. The spindle lock is mounted on
the output spindle between the first and second ends. The front and
rear bearings, which are disposed on opposite sides of the spindle
lock, support the output spindle relative to the housing for
rotation about a spindle axis.
Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
The drawings described herein are for illustrative purposes only of
selected embodiments and not all possible implementations, and are
not intended to limit the scope of the present disclosure.
FIG. 1 is a side elevation view of an exemplary tool constructed in
accordance with the teachings of the present disclosure;
FIG. 2 is an exploded perspective view of the tool of FIG. 1;
FIG. 3 is a longitudinal section view of a portion of the tool of
FIG. 1; and
FIGS. 4 through 6 are section views of portions of five other tools
constructed in accordance with the teachings of the present
disclosure.
Corresponding reference numerals indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION
With reference to FIGS. 1 and 2 of the drawings, a power tool
constructed in accordance with the teachings of the present
disclosure is generally indicated by reference numeral 10. As those
skilled in the art will appreciate, the power tool 10 may be either
a corded (e.g., AC powered) or cordless (e.g., DC battery operated)
device, such as a portable screwdriver, impact driver, drill/driver
or hammer drill/drill. In the particular embodiment illustrated,
the power tool 10 is a cordless screwdriver having a housing 12, a
motor assembly 14, a transmission assembly 16, an output spindle
18, a spindle lock 20, a clutch mechanism 22, a chuck 24, a trigger
assembly 26 and a battery pack 28. Those skilled in the art will
understand that several of the components of power tool 10, such as
the chuck 24, the trigger assembly 26 and the battery pack 28, are
conventional in nature and need not be described in significant
detail in this application. Reference may be made to a variety of
publications for a more complete understanding of the operation of
the conventional features of power tool 10. One example of such
publications is commonly assigned U.S. Pat. No. 5,897,454 issued
Apr. 27, 1999, the disclosure of which is hereby incorporated by
reference as if fully set forth herein.
The housing 12 can include a pair of clam shell housing halves 40
only one shown in FIG. 2) that can cooperate to define a body 42, a
handle 44 and a battery interface 46 that can be configured to
receive the battery pack 28. The handle 44 can house the trigger
assembly 26 in a conventional manner, while the body 42 can define
a motor cavity 48 into which the motor assembly 14 can be received.
The housing 12 can be configured with an exterior gear case housing
(not shown) that can be coupled to a front side of the body 42 and
configured to shroud or cover all or portions of the transmission
assembly 16 and clutch mechanism 22. In the particular example
provided, however, the clam shell housing halves 40 are configured
to shroud or cover the transmission assembly 16 and the clutch
mechanism 22.
With reference to FIGS. 2 and 3, the motor assembly 14 can comprise
a motor 60 and an adapter plate 62. The motor 60 can be any type of
motor, such as a DC electric motor, and can include an output shaft
64. The motor 60 can be received in the motor cavity 48 and can be
electrically coupled to the trigger assembly 26 and the battery
pack 28. The adapter plate 62 can be fixedly coupled to an end of
the motor 60.
The transmission assembly 16 can comprise a transmission housing 80
and a transmission 82. The transmission housing 80 can be a hollow,
generally tubular structure that is configured to house the
transmission 82 and portions of the clutch mechanism 22. The
transmission housing 80 can be received into the motor cavity 48
and can engage the clam shell housing halves 40 such that the
transmission housing 80 is axially fixed and non-rotatably engaged
to the housing 12. The transmission housing 80 can define a front
bearing mount 90 and a central cavity 92 having a first shoulder
94, a second shoulder 96 and a third shoulder 98.
The transmission 82 can be a planetary-type transmission having an
input planetary stage 110 and an output planetary stage 112 that
can be received in the central cavity 92 of the transmission
housing 80. It will be appreciated that although the particular
transmission depicted and described herein is a two-stage, single
speed transmission, the teachings of the present disclosure have
application to other types of transmissions, including those that
are operable in more than one speed ratio and/or those that
comprise fewer or more than two planetary stages (i.e., a single
stage planetary transmission or a transmission having at least one
planetary stage disposed between the input and output planetary
stages 110 and 112). The input planetary stage 110 can comprise an
input sun gear 120, a plurality of input planet gears 122, an input
planet carrier 124 and an input ring gear 126, while the output
planetary stage 112 can comprise an output sun gear 130, a
plurality of output planet gears 132, an output planet carrier 134
and an output ring gear 136.
The input sun gear 120 can be mounted on the output shaft 64 of the
motor 60 for rotation therewith. The input planet gears 122 can be
meshingly engaged with the input sun gear 120 and the input ring
gear 126. The input planet carrier 124 can comprise a carrier body
140 and a plurality of pins 142 that can be mounted to the carrier
body 140. Each of the input planet gears 122 can be rotatably
mounted on a respective one of the pins 142. The input ring gear
126 can be abutted against the first shoulder 94. The adapter plate
62 can be received in the central cavity 92 and non-rotatably
coupled to the transmission housing 80 to thereby limit rearward
axial movement of the input ring gear 126 relative to the
transmission housing 80, as well as to inhibit rotation of the
motor 60 relative to the transmission housing 80.
The output sun gear 130 can be coupled to the carrier body 140 of
the input planet carrier 124 for rotation therewith. The output
planet gears 132 can be meshingly engaged with the output sun gear
130 and the output ring gear 136. The output planet carrier 134 can
comprise a carrier body 150 and a plurality of pins 152 that can be
mounted to the carrier body 150. Each of the output planet gears
132 can be rotatably mounted on a respective one of the pins 152 of
the output carrier 134. The output ring gear 136 can be abutted
against the second shoulder 96 and non-rotatably engaged to the
transmission housing 80. In the particular example provided, the
output ring gear 136 includes a plurality of external teeth 160
that are engaged to internal teeth 162 formed on the interior of
the transmission housing 80 proximate the second shoulder 96.
The output spindle 18 can be a unitarily formed shaft structure
that can be received at least partially through the transmission
82. The output spindle 18 can comprise a rear end 170, a front end
172 and an anvil mount 174 that can be disposed between the rear
and front ends 170 and 172. The rear end 170 can be generally
cylindrically shaped and can extend fully or partly through the
input planetary stage 110 where it can be supported for rotation by
an element of the transmission 82. For example, the rear end 170
can extend through or into at least one of the output sun gear 130
and the carrier body 140 of the input planet carrier 124 such that
the input planet carrier 124 supports the rear end 170 of the
output spindle 18. The output shaft 64 of the motor 60 can be
received in an appropriately sized aperture 180 in the rear end 170
of the output spindle 18.
A suitable rear bearing 190, such as a journal bearing or bushing,
can be disposed between the transmission housing 80 and the carrier
body 140 of the input planet carrier 124 to support the input
planet carrier 124 for rotation about a spindle axis 200. It will
be appreciated that the rear bearing 190, which can be disposed
axially between the input ring gear 126 and the output ring gear
136, can indirectly support the rear end 170 of the output spindle
18 about the spindle axis 200.
A suitable front bearing 210, such as a ball bearing, can be
disposed in the front bearing mount 90 between the transmission
housing 80 and the front end 172 of the output spindle 18. The
front end 172 can be configured to transmit rearwardly-directed
thrust loads into the front bearing 210 so that they may be
transmitted into the transmission housing 80. One or more snap
rings or other retaining devices can be employed to limit axial
movement of the front bearing 210 on the front end 172 of the
output spindle 18.
The spindle lock 20 can comprise an outer collar 220, a plurality
of lock pins 222, a plurality of projections 224, which can be
integrally formed with the carrier body 150 of the output planet
carrier 134, and an anvil 226. The outer collar 220 can be an
annular structure that can be received against the third shoulder
98 in the central cavity 92 and non-rotatably engaged to the
transmission housing 80. The lock pins 222 can extend
longitudinally parallel to the spindle axis 200 between the
projections 224 and an interior surface of the outer collar 220.
The anvil 226 can be mounted on the anvil mount 174 on the output
spindle 18 such that the anvil 226 is coupled to the output spindle
18 for rotation therewith. The spindle lock 20 is configured to
permit the output spindle 18 to rotatably driven by the
transmission 82, but to lock the output spindle 18 to the
transmission housing 80 (to thereby inhibit rotation of the output
spindle 18) when the output spindle 18 is rotated manually.
The clutch mechanism 22 can include a clutch member 250, one or
more engagement assemblies 252 and an adjustment mechanism 254. The
clutch member 250 can be an annular structure that can be fixedly
coupled to the input ring gear 126. In the particular example
provided, the clutch member 250 includes an arcuate clutch face 260
that is formed into an axially forward facing side of the input
ring gear 126. The outer diameter of the clutch member 250 is sized
to rotate within the portion of the central cavity 92 that is
proximate the first shoulder 94 in the transmission housing 80.
While the input ring gear 126 and the clutch member 250 have been
illustrated as a one piece (i.e., unitarily formed) construction,
those skilled in the art will understand that they may be
constructed otherwise.
In the particular embodiment illustrated, the engagement assemblies
252 are disposed 180.degree. apart from one another (only one is
shown in FIG. 3 for clarity) and each engagement assembly 252
includes a pin member 270, a follower spring 272 and a follower
274. The pin member 270 includes a cylindrical body portion 280
having an outer diameter that is sized to slip-fit within an
actuator aperture 284 that is formed through the transmission
housing 80. A first end of the pin member 270 can have an end that
can be defined by a spherical radius and can be configured to
engage the adjustment mechanism 254.
The follower spring 272 can be a compression spring whose outside
diameter is sized to slip fit within the actuator aperture 284. The
forward end of the follower spring 272 can contacts the pin member
270, while the opposite end of the follower spring 272 can contact
the follower 274. An end portion of the follower 274 can be
cylindrical in shape and sized to slip fit within the inside
diameter of the follower spring 272. In this regard, the end
portion of the follower 274 can act as a spring follower to prevent
the follower spring 272 from bending over when it is compressed.
The follower 274 can also include a cylindrically shaped body
portion, which can be sized to slip fit within the actuator
aperture 284, and a tip portion that is configured to extend
axially through the first shoulder 94 and engage the clutch face
260. In the particular example illustrated, the tip portion is
defined by a spherical radius.
The adjustment mechanism 254 can include a setting collar 322 can
be shaped in the form of a generally hollow cylinder that is sized
to fit and cover a front end of the housing 12. The setting collar
322 can include an annular face into which an adjustment profile
330 is formed. The adjustment profile 330 can be tapered or stepped
such that rotation of the setting collar 322 will cause
corresponding axial movement of the pin member 270, which operates
to change the torque setting of the clutch mechanism 22 as a result
of corresponding compression or extension of the follower spring
272.
The setting collar 322 can include a contoured outer surface that
can permit the user of the tool 10 to comfortably rotate both the
setting collar 322 to set the adjustment profile 330 at a position
corresponding to a desired torque setting of the clutch mechanism
22.
During the operation of the tool 10, an initial drive torque is
transmitted by the output shaft 64 of the motor 60 to the input
planetary stage 110, causing the input planet gears 122 to rotate.
Rotation of the input planet gears 122 creates a first intermediate
torque that is applied against the input ring gear 126. A clutch
torque applied by the clutch mechanism 22 resists the first
intermediate torque to thereby prevent the input ring gear 126 from
rotating within the transmission housing 80 such that the first
intermediate torque is applied to the input planet carrier 124 and
the remainder of the transmission 82 so as to multiply the first
intermediate torque in a predetermined manner according to the
reduction ratio of the transmission 82.
A portion of another power tool 10a constructed in accordance with
the teachings of the present disclosure is schematically
illustrated in FIG. 4. In the example provided, the transmission
82a includes an input planetary stage 110a, an intermediate
planetary stage 500, and an output planetary stage 112a. The output
spindle 18a extends through the transmission 82a such that the rear
end 170a of the output spindle 18a is received through or into at
least one of an intermediate sun gear 504 (which is associated with
the intermediate planetary stage 500) and the carrier body 140a of
the input planet carrier 124a such that the input planet carrier
124a supports the rear end 170a of the output spindle 18a. The rear
bearing 190a can be disposed between the transmission housing 80a
and an element of the transmission 82a located rearwardly of the
final or output stage of the transmission 82a (i.e., rearwardly of
the output planetary stage 112a). In the particular example
provided, the rear bearing 190a is disposed between the
transmission housing 80a and the carrier body 140a of the input
planet carrier 124a to support the input planet carrier 124a for
rotation about the spindle axis 200a. As with the previous example,
the front bearing 210a is received in a front bearing mount 90a
formed in a transmission housing 80a and cooperates to align front
end 172a of the output spindle 18a to the spindle axis 200a.
In the particular example provided, the transmission 82a is a
two-speed, three-stage planetary-type transmission in which a ring
gear 510 associated with the intermediate planetary stage 500 is
movable between a first position (shown), in which the ring gear
510 is meshingly engaged to the planet gears 520 and a toothed
exterior surface 522 of the planet carrier 524 of the intermediate
planetary stage 500, and a second position in which the ring gear
510 is translated axially rearwardly so as to non-rotatably engage
the rear bearing 190a and disengage the toothed exterior surface
522 of the planet carrier 524 of the intermediate planetary stage
500. Moreover, the clutch mechanism 22a is configured to resist
rotation of the output ring gear 136a.
A portion of another power tool 10b constructed in accordance with
the teachings of the present disclosure is schematically
illustrated in FIG. 5. This example is generally similar to that of
FIGS. 1-3, except that a pair of motor bearings 600 support the
output shaft 64b (relative to the housing 12b) on opposite sides of
the motor 60b, the output spindle 18b extends into the input sun
gear 120b, the output shaft 64b of the motor 60b does not extend
into the rear end 170b of the output spindle 18b, and the rear
bearing 190b is received between the input sun gear 120b and the
rear end 170b of the output spindle 18b (rather than between the
carrier body 140b of the input planet carrier 124b and the
transmission housing 80b).
A portion of another power tool 10c constructed in accordance with
the teachings of the present disclosure is schematically
illustrated in FIG. 6. This example is generally similar to that of
FIGS. 1-3, except that a pair of motor bearings 600 support the
output shaft 64c (relative to the housing 12c) on opposite sides of
the motor 64c and the rear bearing 190c is received between the
output shaft 64c of the motor 60c and the rear end 170c of the
output spindle 18c (rather than between the carrier body 140c of
the input planet carrier 124c and the transmission housing
80c).
The foregoing description of the embodiments has been provided for
purposes of illustration and description. It is not intended to be
exhaustive or to limit the invention. Individual elements or
features of a particular embodiment are generally not limited to
that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the invention, and all such modifications are intended to be
included within the scope of the invention.
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