GB2117485A - A planetary gear train - Google Patents

A planetary gear train Download PDF

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Publication number
GB2117485A
GB2117485A GB08208310A GB8208310A GB2117485A GB 2117485 A GB2117485 A GB 2117485A GB 08208310 A GB08208310 A GB 08208310A GB 8208310 A GB8208310 A GB 8208310A GB 2117485 A GB2117485 A GB 2117485A
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GB
United Kingdom
Prior art keywords
gear
gears
planet
sun
ring gear
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.)
Granted
Application number
GB08208310A
Other versions
GB2117485B (en
Inventor
John Fickling
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.)
Air Compressors and Tools Ltd
Original Assignee
Desoutter Ltd
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 Desoutter Ltd filed Critical Desoutter Ltd
Priority to GB08208310A priority Critical patent/GB2117485B/en
Publication of GB2117485A publication Critical patent/GB2117485A/en
Application granted granted Critical
Publication of GB2117485B publication Critical patent/GB2117485B/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • F16H1/46—Systems consisting of a plurality of gear trains each with orbital gears, i.e. systems having three or more central gears

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Retarders (AREA)
  • Drilling And Boring (AREA)

Abstract

The planetary gear train comprises coaxial input and output sun gears (12) and (17) respectively axially spaced apart, a fixed ring gear (11) coaxial with and surrounding the two sun gears, and a planet carrier (21) between the two sun gears. The planet carrier carries first planet gears (22) meshing with the input sun gear and the ring gear and second planet gears (23) meshing with the output sun gear and the ring gear. The gear train may be used to provide gear reduction between a motor (15) and a tool holder of a power tool, in which case the input sun gear has less teeth than the output sun gear. <IMAGE>

Description

SPECIFICATION A gear train This invention relates to an epicyclic gear train particularly but not exclusively for use in hand held power tools.
Due to the physical proportions of known epicyclic gear trains for hand held power tools, it has not been possible to obtain a gear reduction of less than 3:1.
The invention provides in one aspect an epicyclic gear train comprising coaxial input and output sun gears axially spaced apart, a fixed ring gear coaxial with and surrounding the two sun gears, and a planet carrier between the two sun gears, the planet carrier carrying first and second planet gears, the first planet gear(s) meshing with the input sun gear and the ring gear and the second planet gear(s) meshing with the output sun gear and the ring gear.
Preferably, the input sun gear has less teeth than the output gear so as to give a gear reduction.
Advantageously, there are three first planet gears and three second planet gears.
The invention provides in a second aspect a power tool provided with an epicyclic gear train according to the first aspect of the invention, the gear train being connected between a motor and a tool holder.
Preferably, the output sun gear is connected to the tool holder via a clutch, e.g. a torque sensitive clutch.
The invention will now be more particularly described with reference to the accompanying drawing which is a longitudinal section through one embodiment of a gear train according to the invention, connected to an electric motor.
Referring to the drawing, the gear train shown therein is intended primarily for use in hand held power tools and comprises a casing 10 housing a fixed ring gear 11. An input sun gear 12 is formed on the end of a shaft 13 connected to the rotor 14 of an electric or pneumatic motor 15 attached to the casing 10. The shaft 13 is supported for rotation in a bearing 16 and is coaxial with the ring gear 11. An output sun gear 17 is mounted on a spindle 18. The spindle 18 is supported for rotation in bearings 19 and 20 and is coaxial with the sun gear 12 and the ring gear 11.
The gears 12 and 17 are axially spaced apart and a planet carrier 21 is located between them. The planet carrier 21 carries three planet gears 22 (only one shown) on one side and three planet gears 23 (only one shown) on the other side. The gears 22 are rotatably mounted on equi-angularly spaced spindles 24 and the gears 23 are rotatably mounted on equi-angularly spaced spindles 25. The gears 22 mesh with the sun gear 12 and the ring gear 11 and the gears 23 mesh with the sun gear 17 and the ring gear 11.
In operation the planet carrier rotates about the axis of the gears 11, 12 and 17 but is supported in this rotation only by the meshing engagement of the planet gears 22 and 23 with the ring gear and respective sun gears.
The gear train shown has less teeth on sun gear 12 than on sun gear 17 and hence, gives a gear reduction between the shaft 13 and spindle 18.
As an example, the ring gear has 46 teeth, the sun gear 12 has 8 teeth and the sun gear 17 has 17 teeth.
Hence the reduction ratio between the shaft 13 and planet carrier 21 is given by: (46 . 8) + 1 = 6.75:1 The increased ratio between the planet carrier 21 and the spindle 18 is given by: (46 . 17) + 1 = 3.7:1 Hence, the overall reduction ratio between the shaft 13 and spindle 18 is 6.75 . 3.7 = 1.82:1.
A spindle 18 drives a tool holder (not shown) either directly or via a torque sensitive clutch and hence the reduction ratio between the rotor 14 and tool will also be 1.82:1.
Although, described in conjunction with a power tool, the above described gear train may find other applications.
If desired, the ring gear 11 can have more teeth at that one end which is in mesh with the planet gears 22 that at the other end which is in mesh with the other planet gears 23.
1. An epicyclic gear train comprising coaxial input and output sun gears axially spaced apart, a fixed ring gear coaxial with and surrounding the two sun gears, and a planet carrier between the two sun gears, the planet carrier carrying first and second planet gears, the first planet gear(s) meshing with the input sun gear and the ring gear and the second planet gear(s) meshing with the output sun gear and the ring gear.
2. The epicyclic gear train of claim 1, wherein the input sun gear has less teeth than the output sun gear so as to give a gear reduction.
3. The epicyclic gear train of claim 1 or claim 2, wherein there are three first planet gears and three second planet gears.
4. A power tool having a motor, a tool holder and an epicyclic gear train according to any one of claims 1 to 3, the gear train being connected between the motor and the tool holder.
5. The power tool of claim 4, wherein the output sun gear is connected to the tool holder via a clutch.
6. The power tool of claim 5, wherein the clutch is a torque sensitive clutch.
7. An epicyclic gear train substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
8. A power tool substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
New claims or amendments to claims filed on 7 Oct 1982 Superseded claims 1 New or amended claims:
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    SPECIFICATION A gear train This invention relates to an epicyclic gear train particularly but not exclusively for use in hand held power tools.
    Due to the physical proportions of known epicyclic gear trains for hand held power tools, it has not been possible to obtain a gear reduction of less than 3:1.
    The invention provides in one aspect an epicyclic gear train comprising coaxial input and output sun gears axially spaced apart, a fixed ring gear coaxial with and surrounding the two sun gears, and a planet carrier between the two sun gears, the planet carrier carrying first and second planet gears, the first planet gear(s) meshing with the input sun gear and the ring gear and the second planet gear(s) meshing with the output sun gear and the ring gear.
    Preferably, the input sun gear has less teeth than the output gear so as to give a gear reduction.
    Advantageously, there are three first planet gears and three second planet gears.
    The invention provides in a second aspect a power tool provided with an epicyclic gear train according to the first aspect of the invention, the gear train being connected between a motor and a tool holder.
    Preferably, the output sun gear is connected to the tool holder via a clutch, e.g. a torque sensitive clutch.
    The invention will now be more particularly described with reference to the accompanying drawing which is a longitudinal section through one embodiment of a gear train according to the invention, connected to an electric motor.
    Referring to the drawing, the gear train shown therein is intended primarily for use in hand held power tools and comprises a casing 10 housing a fixed ring gear 11. An input sun gear 12 is formed on the end of a shaft 13 connected to the rotor 14 of an electric or pneumatic motor 15 attached to the casing 10. The shaft 13 is supported for rotation in a bearing 16 and is coaxial with the ring gear 11. An output sun gear 17 is mounted on a spindle 18. The spindle 18 is supported for rotation in bearings 19 and 20 and is coaxial with the sun gear 12 and the ring gear 11.
    The gears 12 and 17 are axially spaced apart and a planet carrier 21 is located between them. The planet carrier 21 carries three planet gears 22 (only one shown) on one side and three planet gears 23 (only one shown) on the other side. The gears 22 are rotatably mounted on equi-angularly spaced spindles 24 and the gears 23 are rotatably mounted on equi-angularly spaced spindles 25. The gears 22 mesh with the sun gear 12 and the ring gear 11 and the gears 23 mesh with the sun gear 17 and the ring gear 11.
    In operation the planet carrier rotates about the axis of the gears 11, 12 and 17 but is supported in this rotation only by the meshing engagement of the planet gears 22 and 23 with the ring gear and respective sun gears.
    The gear train shown has less teeth on sun gear 12 than on sun gear 17 and hence, gives a gear reduction between the shaft 13 and spindle 18.
    As an example, the ring gear has 46 teeth, the sun gear 12 has 8 teeth and the sun gear 17 has 17 teeth.
    Hence the reduction ratio between the shaft 13 and planet carrier 21 is given by: (46 . 8) + 1 = 6.75:1 The increased ratio between the planet carrier 21 and the spindle 18 is given by: (46 . 17) + 1 = 3.7:1 Hence, the overall reduction ratio between the shaft 13 and spindle 18 is
    6.75 . 3.7 = 1.82:1.
    A spindle 18 drives a tool holder (not shown) either directly or via a torque sensitive clutch and hence the reduction ratio between the rotor 14 and tool will also be 1.82:1.
    Although, described in conjunction with a power tool, the above described gear train may find other applications.
    If desired, the ring gear 11 can have more teeth at that one end which is in mesh with the planet gears 22 that at the other end which is in mesh with the other planet gears 23.
    1. An epicyclic gear train comprising coaxial input and output sun gears axially spaced apart, a fixed ring gear coaxial with and surrounding the two sun gears, and a planet carrier between the two sun gears, the planet carrier carrying first and second planet gears, the first planet gear(s) meshing with the input sun gear and the ring gear and the second planet gear(s) meshing with the output sun gear and the ring gear.
    2. The epicyclic gear train of claim 1, wherein the input sun gear has less teeth than the output sun gear so as to give a gear reduction.
    3. The epicyclic gear train of claim 1 or claim 2, wherein there are three first planet gears and three second planet gears.
    4. A power tool having a motor, a tool holder and an epicyclic gear train according to any one of claims 1 to 3, the gear train being connected between the motor and the tool holder.
    5. The power tool of claim 4, wherein the output sun gear is connected to the tool holder via a clutch.
    6. The power tool of claim 5, wherein the clutch is a torque sensitive clutch.
    7. An epicyclic gear train substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
    8. A power tool substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
    New claims or amendments to claims filed on 7 Oct 1982 Superseded claims 1 New or amended claims:
    1. An epicyclicgeartrain having a non direct gear ratio and comprising coaxial input and output sun gears axially spaced apart, a fixed ring gear coaxial with and surrounding the two sun gears, and a planet carrier between the two sun gears, the planet carrier carrying first and second planet gears, the first planet gear(s) meshing with the input sun gear and the ring gear and the second planet gear(s) meshing with the output sun gear and the ring gear.
GB08208310A 1982-03-22 1982-03-22 A planetary gear train Expired GB2117485B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08208310A GB2117485B (en) 1982-03-22 1982-03-22 A planetary gear train

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08208310A GB2117485B (en) 1982-03-22 1982-03-22 A planetary gear train

Publications (2)

Publication Number Publication Date
GB2117485A true GB2117485A (en) 1983-10-12
GB2117485B GB2117485B (en) 1985-06-05

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2186342A (en) * 1986-02-06 1987-08-12 Johnson Electric Ind Mfg An electric motor and gearbox unit and component parts thereof
WO2003042576A1 (en) * 2001-11-13 2003-05-22 Shubur Co., Ltd. Speed change system using planetary gear assembly
DE10324362A1 (en) * 2003-05-27 2004-12-16 A. Friedr. Flender Ag Gear for driving a rotary tube
CN114454048A (en) * 2020-11-10 2022-05-10 施耐宝公司 Pneumatic tool with gear train

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB649221A (en) * 1948-10-25 1951-01-24 Austin Motor Co Ltd Means for timing the fuel injection period in diesel engines

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB649221A (en) * 1948-10-25 1951-01-24 Austin Motor Co Ltd Means for timing the fuel injection period in diesel engines

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2186342A (en) * 1986-02-06 1987-08-12 Johnson Electric Ind Mfg An electric motor and gearbox unit and component parts thereof
US4763031A (en) * 1986-02-06 1988-08-09 Johnson Electric Industrial Manufactory Limited Electric motor and gearbox unit and component parts thereof
WO2003042576A1 (en) * 2001-11-13 2003-05-22 Shubur Co., Ltd. Speed change system using planetary gear assembly
DE10324362A1 (en) * 2003-05-27 2004-12-16 A. Friedr. Flender Ag Gear for driving a rotary tube
US7112157B2 (en) 2003-05-27 2006-09-26 A. Friedr. Flender Aktiengesellschaft Gear unit for the drive of a rotation tube
CN114454048A (en) * 2020-11-10 2022-05-10 施耐宝公司 Pneumatic tool with gear train

Also Published As

Publication number Publication date
GB2117485B (en) 1985-06-05

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Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19970322