WO2006000907A1 - Hydraulic actuators - Google Patents

Hydraulic actuators Download PDF

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Publication number
WO2006000907A1
WO2006000907A1 PCT/IB2005/001982 IB2005001982W WO2006000907A1 WO 2006000907 A1 WO2006000907 A1 WO 2006000907A1 IB 2005001982 W IB2005001982 W IB 2005001982W WO 2006000907 A1 WO2006000907 A1 WO 2006000907A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
pedal
master cylinder
push rod
recess
Prior art date
Application number
PCT/IB2005/001982
Other languages
French (fr)
Inventor
Filipe Franco
Original Assignee
Luk Lamellen Und Kupplungsbau Beteiligungs Kg
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 Luk Lamellen Und Kupplungsbau Beteiligungs Kg filed Critical Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority to DE112005001358.8T priority Critical patent/DE112005001358B4/en
Publication of WO2006000907A1 publication Critical patent/WO2006000907A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/16—Master control, e.g. master cylinders
    • B60T11/165—Single master cylinders for pressurised systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/16—Master control, e.g. master cylinders
    • B60T11/18—Connection thereof to initiating means
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D25/00—Fluid-actuated clutches
    • F16D25/08—Fluid-actuated clutches with fluid-actuated member not rotating with a clutching member
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D25/00—Fluid-actuated clutches
    • F16D25/08—Fluid-actuated clutches with fluid-actuated member not rotating with a clutching member
    • F16D2025/081—Hydraulic devices that initiate movement of pistons in slave cylinders for actuating clutches, i.e. master cylinders
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0215—Control by fluid pressure for damping of pulsations within the fluid system

Definitions

  • This invention relates to hydraulic actuators and in particular, though not exclusively, to such actuators used as master cylinders in an hydraulic system for the operation of a vehicle clutch.
  • a hydraulic master cylinder comprising a housing, a piston in sealed sliding contact with a bore in the housing to define a working chamber ahead of a working surface on the piston, a push rod connected at one end with the piston and at the other end with a pedal-operated linkage, and an elastomeric damper disposed in the thrust path between the other end of the push rod and the working surface of the piston, the master cylinder being characterised in that the damper comprises a body of elastomeric material having one or more clearances or cavities which are normally open when the piston is not actuated by the push rod to provide a first low stiffness connection between the pedal and piston and which are closed when the pedal is actuated to give a second higher stiffness connection in the thrust path from the pedal to the piston.
  • the damper comprises a body of elastomeric material having one or more clearances or cavities which are normally open when the piston is not actuated by the push rod to provide a first low stiffness connection between the pedal and piston and which are closed when the pedal is
  • the body of elastomeric material is received in a recess, the body having an outer peripheral zone connected with the remainder of the body by a flexible annular web, this outer peripheral zone contacts a base of the recess and provides by deflection of the web a first low stiffness connection between the piston and the pedal, the actuation of the master cylinder causing the web to deflect to allow a central region in the body of elastomeric material radially within the outer peripheral zone to contact the base of the recess to provide a solid elastomeric connection between the piston and pedal at the second higher stiffness.
  • the recess may be formed in a first part of the piston which provides the working surface of the piston and the body of elastomeric material is compressed in the recess between a second portion of the piston connected with the push rod and the first part of the piston.
  • Figure 1 is an external view of a master cylinder in accordance with the present invention shown partly in section;
  • Figure 2 shows, on a larger scale, the sectioned portion of figure 1 .
  • Figures 3, 4 and 5 show the progressive compression of an elastomeric damping block used in the master cylinder of figure 1 as the master cylinder is actuated.
  • the master cylinder 10 has a body 11 with a bore 12 in which a piston 13 is in sealed sliding cooperation. Piston 13 is displaced within bore 12 by a push rod 14 which has a ball joint connection 15 with an associated clutch operating pedal (not shown).
  • the master cylinder has an inlet 16 connected with a reservoir and an outlet 17 connected by a conduit (not shown) to an associated slave cylinder for operation of a vehicle clutch.
  • Piston 13 comprises a first part 18 which carries a seal 19 which contacts bore 12 (and which provides a working surface which compresses the fluid to the left of piston part 18 as viewed in the drawings) and a second part 20 provided with a part spherical concave recess 21 which cooperates with a part spherical convex surface 22 formed on a head portion 23 of push rod 14.
  • the part spherical surfaces 21 and 22 permitting limited articulation of the push rod 14 relative to the piston 18,20.
  • the push rod 14 is retained within body 11 by a split ring 24.
  • the piston part 18 includes a recess 25 within which an elastomeric damping block 26 is located.
  • a projection 27 on the second piston part 20 also extends into recess 25 so that the elastomeric body 26 is confined between the two piston parts 18 and 20.
  • Elastomeric damping block 26 has an outer annular peripheral zone 28 which is connected with the main body portion 29 by a flexible annular web 30 thus defining an annular cavity 31 behind the outer peripheral zone 28.
  • a central zone 32 Radially within the outer peripheral zone 28 is a central zone 32.
  • the elastomeric body is attached to projection 27 by a radially inwardly extending flange portion 33 which engages a groove 34 in projection 27.
  • Figure 2 shows the master cylinder in the unactuated condition in which the operators foot is not resting on the associated clutch operating pedal.
  • This condition is also shown in figure 3 which shows half of the elastomeric block 26 and the cooperating portions 18 and 20 of the piston.
  • the central portion 32 of the elastomeric body is spaced (see clearance "x") from the bottom of recess 25. If the operator now rests his foot on the pedal without intending to depress the pedal, as many operators do, the force applied to the pedal by the weight of his foot will cause annular web 30 to flex thus providing a first low stiffness connection between the pedal and piston part 18 thereby providing good damping of any vibrations in the actuating fluid.
  • the elastomeric body 26 thus provides a first low level of stiffness when the driver is simply resting his foot on the pedal and the annular web 30 is flexing to provide good isolation of the operator's foot from any vibrations in the fluid and a second higher level of stiffness when the central portion 32 of the body contacts the base of the recess 25 and the operator is actively depressing the pedal.

Abstract

A hydraulic master cylinder (10) has a housing (11), a piston (13) in sealed sliding contact with a bore (12) in the housing to define a working chamber ahead of a working surface on the piston, a push rod (14) connected at one end (23) with the piston and at the other end (15) with a pedal-operated linkage, and an elastomeric damper (26) disposed in the thrust path between the other end of the push rod and the working surface of the piston. The damper includes a body (26) of elastomeric material which has one or more clearances or cavities (x,31) which are normally open when the piston (13) is not actuated by the push rod (14) to provide a first low stiffness connection between the pedal and piston and which are closed when the pedal is actuated to give a second higher stiffness connection in the thrust path from the pedal to the piston.

Description

HYDRAULIC ACTUATORS
This invention relates to hydraulic actuators and in particular, though not exclusively, to such actuators used as master cylinders in an hydraulic system for the operation of a vehicle clutch.
One of the problems with such systems is the damping of the vibrations induced in the pressurised fluid of the system by the associated clutch and vehicle driveline to prevent the transmission to the vehicle operator of unacceptable noise or physical vibrations through the clutch pedal.
Many solutions have been proposed to damp such vibrations in the system fluid, for example by damping the movement of the fluid itself or interposing elastomeric components in the connection between the pedal and fluid. Sometimes both types of damper may be used in the same installation.
It is an object of the present invention to provide a master cylinder which includes an improved form of damping and which is particularly suitable for use with a clutch actuating system.
Thus according to the present invention there is provided a hydraulic master cylinder comprising a housing, a piston in sealed sliding contact with a bore in the housing to define a working chamber ahead of a working surface on the piston, a push rod connected at one end with the piston and at the other end with a pedal-operated linkage, and an elastomeric damper disposed in the thrust path between the other end of the push rod and the working surface of the piston, the master cylinder being characterised in that the damper comprises a body of elastomeric material having one or more clearances or cavities which are normally open when the piston is not actuated by the push rod to provide a first low stiffness connection between the pedal and piston and which are closed when the pedal is actuated to give a second higher stiffness connection in the thrust path from the pedal to the piston. Such an arrangement is particularly suitable for use as a master cylinder in a clutch operating system.
In a preferred arrangement the body of elastomeric material is received in a recess, the body having an outer peripheral zone connected with the remainder of the body by a flexible annular web, this outer peripheral zone contacts a base of the recess and provides by deflection of the web a first low stiffness connection between the piston and the pedal, the actuation of the master cylinder causing the web to deflect to allow a central region in the body of elastomeric material radially within the outer peripheral zone to contact the base of the recess to provide a solid elastomeric connection between the piston and pedal at the second higher stiffness.
The recess may be formed in a first part of the piston which provides the working surface of the piston and the body of elastomeric material is compressed in the recess between a second portion of the piston connected with the push rod and the first part of the piston.
One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which :
Figure 1 is an external view of a master cylinder in accordance with the present invention shown partly in section;
Figure 2 shows, on a larger scale, the sectioned portion of figure 1 , and
Figures 3, 4 and 5 show the progressive compression of an elastomeric damping block used in the master cylinder of figure 1 as the master cylinder is actuated.
Referring to the drawings, the master cylinder 10 has a body 11 with a bore 12 in which a piston 13 is in sealed sliding cooperation. Piston 13 is displaced within bore 12 by a push rod 14 which has a ball joint connection 15 with an associated clutch operating pedal (not shown).
The master cylinder has an inlet 16 connected with a reservoir and an outlet 17 connected by a conduit (not shown) to an associated slave cylinder for operation of a vehicle clutch.
Piston 13 comprises a first part 18 which carries a seal 19 which contacts bore 12 (and which provides a working surface which compresses the fluid to the left of piston part 18 as viewed in the drawings) and a second part 20 provided with a part spherical concave recess 21 which cooperates with a part spherical convex surface 22 formed on a head portion 23 of push rod 14. The part spherical surfaces 21 and 22 permitting limited articulation of the push rod 14 relative to the piston 18,20. The push rod 14 is retained within body 11 by a split ring 24.
The piston part 18 includes a recess 25 within which an elastomeric damping block 26 is located. A projection 27 on the second piston part 20 also extends into recess 25 so that the elastomeric body 26 is confined between the two piston parts 18 and 20.
Elastomeric damping block 26 has an outer annular peripheral zone 28 which is connected with the main body portion 29 by a flexible annular web 30 thus defining an annular cavity 31 behind the outer peripheral zone 28.
Radially within the outer peripheral zone 28 is a central zone 32. The elastomeric body is attached to projection 27 by a radially inwardly extending flange portion 33 which engages a groove 34 in projection 27.
Figure 2 shows the master cylinder in the unactuated condition in which the operators foot is not resting on the associated clutch operating pedal. This condition is also shown in figure 3 which shows half of the elastomeric block 26 and the cooperating portions 18 and 20 of the piston. In this condition the central portion 32 of the elastomeric body is spaced (see clearance "x") from the bottom of recess 25. If the operator now rests his foot on the pedal without intending to depress the pedal, as many operators do, the force applied to the pedal by the weight of his foot will cause annular web 30 to flex thus providing a first low stiffness connection between the pedal and piston part 18 thereby providing good damping of any vibrations in the actuating fluid.
If the operator now decides to actuate the clutch pedal the additional force applied to the push rod 14 causes the central portion 32 elastomeric body to contact the base of the recess 25 (see figure 4) so that there is now a solid rubber higher stiffness connection between the piston part 20 and the piston part 18. As the pedal pressure further increases the annular cavity 31 is closed (see figure 5).
The elastomeric body 26 thus provides a first low level of stiffness when the driver is simply resting his foot on the pedal and the annular web 30 is flexing to provide good isolation of the operator's foot from any vibrations in the fluid and a second higher level of stiffness when the central portion 32 of the body contacts the base of the recess 25 and the operator is actively depressing the pedal.

Claims

1. A hydraulic master cylinder (10) comprising a housing (11 ), a piston (13) in sealed sliding contact with a bore (12) in the housing to define a working chamber ahead of a working surface on the piston, a push rod (14) connected at one end (23) with the piston and at the other end (15) with a pedal-operated linkage, and an elastomeric damper (26) disposed in the thrust path between the other end of the push rod and the working surface of the piston, the master cylinder being characterised in that the damper comprises a body (26) of elastomeric material having one or more clearances or cavities (x,31) which are normally open when the piston (13) is not actuated by the push rod (14) to provide a first low stiffness connection between the pedal and piston and which are closed when the pedal is actuated to give a second higher stiffness connection in the thrust path from the pedal to the piston.
2. A master cylinder according to claim 1 characterised in that the body of elastomeric material (26) is received in a recess (25), the body having an outer peripheral zone (28) connected with the remainder of the body by a flexible annular web (30), this outer peripheral zone contacts a base of the recess (25) and provides by deflection of the web (30) a first low stiffness connection between the piston (13) and the pedal, the actuation of the master cylinder causing the web to deflect to allow a central region (32) in the body of elastomeric material radially within the outer peripheral zone to contact the base of the recess (25) to provide a solid elastomeric connection between the piston and pedal at the second higher stiffness.
3. A master cylinder according to claim 2 characterised in that the recess (25) is formed in a first part (18) of the piston (13) which provides the working surface of the piston and the body of elastomeric material (26) is compressed in the recess between a second portion (20) of the piston connected with the push rod (14) and the first part (18) of the piston.
4. A hydraulic master cylinder constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
PCT/IB2005/001982 2004-06-25 2005-06-13 Hydraulic actuators WO2006000907A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112005001358.8T DE112005001358B4 (en) 2004-06-25 2005-06-13 Hydraulic actuators

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0414266.7 2004-06-25
GBGB0414266.7A GB0414266D0 (en) 2004-06-25 2004-06-25 Hydraulic actuators

Publications (1)

Publication Number Publication Date
WO2006000907A1 true WO2006000907A1 (en) 2006-01-05

Family

ID=32800187

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2005/001982 WO2006000907A1 (en) 2004-06-25 2005-06-13 Hydraulic actuators

Country Status (3)

Country Link
DE (1) DE112005001358B4 (en)
GB (1) GB0414266D0 (en)
WO (1) WO2006000907A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017140306A1 (en) * 2016-02-18 2017-08-24 Schaeffler Technologies AG & Co. KG Clutch master cylinder having a damper
US10353422B2 (en) 2015-06-23 2019-07-16 Kongsberg Power Products Systems I, Inc. Bidirectional pedal assembly
US20220196081A1 (en) * 2019-03-11 2022-06-23 Zf Friedrichshafen Ag Claw coupling for interlockingly connecting a first rotatable component to a second rotatable component

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102020112068B4 (en) 2020-05-05 2022-03-03 Schaeffler Technologies AG & Co. KG Piston device of a slave cylinder device and slave cylinder device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2348259A (en) * 1999-02-27 2000-09-27 Luk Lamellen & Kupplungsbau Vibration damping device in a hydraulic circuit operating a clutch
US20030097928A1 (en) * 1999-10-18 2003-05-29 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Master cylinder for use in power trains of motor vehicles

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4325913A1 (en) * 1993-08-02 1995-02-09 Clouth Gummiwerke Ag Spring body
DE19516391B4 (en) * 1994-11-23 2005-09-29 Zf Sachs Ag Hydraulic cylinder for motor vehicle clutch - has housing with axial bore for piston and rod with seal and scraper ring

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2348259A (en) * 1999-02-27 2000-09-27 Luk Lamellen & Kupplungsbau Vibration damping device in a hydraulic circuit operating a clutch
US20030097928A1 (en) * 1999-10-18 2003-05-29 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Master cylinder for use in power trains of motor vehicles

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10353422B2 (en) 2015-06-23 2019-07-16 Kongsberg Power Products Systems I, Inc. Bidirectional pedal assembly
WO2017140306A1 (en) * 2016-02-18 2017-08-24 Schaeffler Technologies AG & Co. KG Clutch master cylinder having a damper
US20220196081A1 (en) * 2019-03-11 2022-06-23 Zf Friedrichshafen Ag Claw coupling for interlockingly connecting a first rotatable component to a second rotatable component
US11739798B2 (en) * 2019-03-11 2023-08-29 Zf Friedrichshafen Ag Claw coupling for interlockingly connecting a first rotatable component to a second rotatable component

Also Published As

Publication number Publication date
GB0414266D0 (en) 2004-07-28
DE112005001358B4 (en) 2015-07-02
DE112005001358T5 (en) 2007-05-31

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