Hydraulic motor with brake assembly

• US 6,345,968 B1
• Filed: 05/10/2000
• Issued: 02/12/2002
• Est. Priority Date: 05/20/1999
• Status: Expired due to Term

• Current Assignee: Parker Intangibles LLC (Parker-Hannifin Corporation)
• Original Assignee: Parker-Hannifin Corporation
• Inventors: Shupe, Brad P.
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): Trieu, Theresa
• Application Number:
  US09/568,636
• Time in Patent Office: 643 Days
• Field of Search: 418/61.3, 418/104, 188/170
• US Class Current: 418/61.3
• CPC Class Codes: F04C 15/0057 Driving elements, brakes, couplings, transmission specially adapted for machines or pumps brakes, couplings, transmissions per se F16, B60
• CPC Class Codes: F04C 15/0084 Brakes, braking assemblies
• CPC Class Codes: F04C 2/104 having an articulated driving shaft
• CPC Class Codes: G08B 5/38 using flashing light
• CPC Class Codes: G08B 7/06 using electric transmission , e.g. involving audible and visible signalling through the use of sound and light sources

Abstract

A hydraulic device includes a housing enclosing a hydraulic motor having a wobble shaft driven by a rotor of a gerotor gear set. An outer end of the wobble shaft is connected to the inner end portion of an output shaft. The output shaft extends axially through the housing and outward from the end of the housing opposite from the motor. A brake assembly holds the motor output shaft against rotation when the hydraulic motor is not operated. The brake assembly includes a series of compression springs provided toward the motor end of the housing, brake disks provided toward the end of the housing opposite from the motor, and an annular piston disposed axially between the springs and the brake disks. The piston and housing include corresponding radial stop surfaces that engage across a major portion of the stop surfaces to prevent over-compression of the springs and the piston from cocking when the piston engages the housing. The housing includes a unitary cup-shaped end cover and unitary housing body which together sealingly enclose the brake disks, annular piston and compression springs therebetween. An axial thrust bearing is provided in the motor pressure zone to axially support the output shaft.

Claims

1. A hydraulic device, comprising:

an axially-extending housing;

a hydraulic motor at one end of the housing having a stator and a rotor with cooperating teeth defining fluid pockets, a wobble shaft connected to said rotor, said rotor rotating and orbiting relative to said stator when hydraulic fluid is directed into and out of the fluid pockets;

an axially-extending output shaft extending outward from another end of the housing, the output shaft having an inner end portion located in the housing and connected to said wobble shaft to rotate said output shaft upon rotation and orbital movement of said rotor;

a brake assembly axially disposed between the one end and the other end of the housing including i) a plurality of annular brake disks interleaved in face-to-face relation with one another, at least some of said disks being fixed to the output shaft for rotation therewith, and other of said brake disks being fixed to the housing;

ii) an annular piston surrounding the output shaft and axially moveable with respect thereto; and

iii) at least one spring device normally biased against one annular surface of the piston to urge said piston toward and against the brake disks to cause said brake disks to brake the output shaft;

an annular fluid pressure cavity defined by another surface of the piston axially-opposite from the one surface to move the piston away from the brake disks when fluid above the force of the spring device enters the cavity, said piston including a radially-projecting stop surface across a major portion of the one surface of the piston and the housing including a corresponding radially-projecting stop surface, the stop surface of the piston engaging the stop surface of the housing at least along the inner diameter of the annular one surface of the piston prior to maximum compression of the spring device, wherein the piston is prevented from cocking when the stop surface of the piston contacts the stop surface of the housing.

2. The hydraulic device as in claim 1, wherein the stop surface of the piston is also along at least the outer diameter of the one annular surface of the piston.

3. The hydraulic device as in claim 1, wherein a plurality of springs are provided normally under compression against the one annular surface of the piston to urge said piston toward and against the brake disks, the springs located in a series of cylindrical cavities formed in the housing, with the housing stop surface radially inwardly and outwardly bounding the cavities.

4. The hydraulic device as in claim 3, wherein the cylindrical cavities for the compression springs open toward the other end of the housing, away from the motor end of the housing.

5. The hydraulic device as in claim 1, wherein the spring device is provided toward the motor end of the housing, the brake disks are provided toward the other end of the housing, and the piston is disposed axially between the spring device and the brake disks.

6. A hydraulic device, comprising:

an axially-extending housing;

a hydraulic motor at one end of the housing having a stator and a rotor with cooperating teeth defining fluid pockets, a wobble shaft connected to said rotor, said rotor rotating and orbiting relative to said stator when hydraulic fluid is directed into and out of the fluid pockets;

an axially-extending output shaft extending outward from another end of the housing, the output shaft having an inner end portion located in the housing and connected to said wobble shaft to rotate said output shaft upon rotation and orbital movement of said rotor;

a brake assembly axially disposed between the one end and the other end of the housing including i) a plurality of annular brake disks interleaved in face-to-face relation with one another, at least some of said disks being fixed to the output shaft for rotation therewith, and other of said brake disks being fixed to the housing;

ii) an annular piston surrounding the output shaft and axially moveable with respect thereto; and

iii) a series of compression springs normally biased against one annular surface of the piston to urge said piston toward and against the brake disks to cause said brake disks to brake the output shaft;

an annular fluid pressure cavity defined by another surface of the piston axially-opposite from the one surface to move the piston away from the brake disks when fluid above the force of the springs enters the cavity;

said housing including a) a unitary, one-piece housing cover at the other end of the housing having a central opening for the output shaft, said housing cover having a cup-shape and receiving and at least partially enclosing the brake disks and the annular piston, and b) a unitary, one-piece housing body toward the one end of the housing having a series of axially-extending cylindrical cavities to receive the compression springs, the cup-shaped housing cover and housing body sealingly enclosing the brake disks, annular piston and compression springs therebetween.

7. The hydraulic device as in claim 6, wherein the cylindrical cavities for the compression springs open toward the other end of the housing, away from the motor end of the housing.

8. The hydraulic device as in claim 7, wherein the housing body is located adjacent the hydraulic motor, and the housing cover is located spaced-apart from the hydraulic motor.

9. The hydraulic device as in claim 6, wherein the compression springs are provided toward the motor end of the housing, the brake disks are provided toward the other end of the housing, and the piston is disposed axially between the springs and the brake disks.

10. A hydraulic device, comprising:

an axially-extending housing;

a hydraulic motor at one end of the housing having a stator and a rotor with cooperating teeth defining fluid pockets, a wobble shaft connected to said rotor, said rotor rotating and orbiting relative to said stator when hydraulic fluid is directed into and out of the fluid pockets;

an axially-extending output shaft extending outward from another end of the housing, the output shaft having an inner end portion located in the housing and connected to said wobble shaft to rotate said output shaft upon rotation and orbital movement of said rotor;

a brake assembly axially disposed between the one end and the other end of the housing including i) a plurality of annular brake disks interleaved in face-to-face relation with one another, at least some of said disks being fixed to the output shaft for rotation therewith, and other of said brake disks being fixed to the housing;

ii) an annular piston surrounding the output shaft and axially moveable with respect thereto; and

iii) at least one spring device normally biased against one annular surface of the piston to urge said piston toward and against the brake disks to cause said brake disks to brake the output shaft;

an annular fluid pressure cavity defined by another surface of the piston axially-opposite from the one surface to move the piston away from the brake disks when fluid above the force of the spring device enters the cavity, the spring device provided toward the one end of the housing, the brake disks provided toward the other end of the housing, and the piston disposed axially between the spring device and the brake disks.

11. The hydraulic device as in claim 10, wherein a plurality of springs are provided normally under compression against the one annular surface of the piston to urge said piston toward and against the brake disks, the springs being located in a series of cylindrical cavities formed in the housing, with the housing stop surface radially inwardly and outwardly bounding the cavities.

12. The hydraulic device as in claim 11, wherein the cylindrical cavities for the compression springs open toward the other end of the housing, away from the motor end of the housing.

13. A hydraulic device, comprising:

an axially-extending housing;

a hydraulic motor at one end of the housing having a stator and a rotor with cooperating teeth defining fluid pockets, a wobble shaft connected to said rotor, said rotor rotating and orbiting relative to said stator when hydraulic fluid is directed into and out of the fluid pockets;

an axially-extending output shaft extending outward from another end of the housing, the output shaft having an inner end portion located in the housing and connected to said wobble shaft to rotate said output shaft upon rotation and orbital movement of said rotor;

a brake assembly axially disposed between the one end and the other end of the housing including i) a plurality of annular brake disks interleaved in face-to-face relation with one another, at least some of said disks being fixed to the output shaft for rotation therewith, and other of said brake disks being fixed to the housing;

ii) an annular piston surrounding the output shaft and axially moveable with respect thereto; and

iii) at least one spring device normally biased against one annular surface of the piston to urge said piston toward and against the brake disks to cause said brake disks to brake the output shaft;

an annular fluid pressure cavity defined by another surface of the piston axially-opposite from the one surface to move the piston away from the brake disks when fluid above the force of the spring device enters the cavity;

an annular seal surrounding the output shaft and blocking flow between the brake assembly and the hydraulic motor; and

a thrust bearing disposed adjacent the inner end of the output shaft in fluid communication with the hydraulic motor, said thrust bearing disposed between radially-extending and opposing bearing surfaces formed in the housing and in the output shaft, said thrust bearing at least partially axially supporting the inner end portion of said output shaft for rotation relative to the housing.

14. The hydraulic device as in claim 13, wherein the annular seal is disposed axially between the thrust bearing and the brake assembly.

15. The hydraulic device as in claim 13, wherein the thrust bearing is located between the inner end of the output shaft and the brake assembly.

16. The hydraulic device as in claim 13, wherein the thrust bearing is located closer to the inner end of the output shaft, than to an outer end of the output shaft extending outwardly from the housing.

17. A hydraulic device, comprising:

an axially-extending housing;

a hydraulic motor at one end of the housing, and a drive linkage to operate the motor, the drive linkage including an axially-extending output shaft extending outward from another end of the housing, the output shaft rotating upon operation of the motor;

a brake assembly axially disposed between the one end and the other end of the housing including i) a plurality of annular brake disks interleaved in face-to-face relation with one another, at least some of said disks being fixed to the output shaft for rotation therewith, and other of said brake disks being fixed to the housing;

ii) an annular piston surrounding the output shaft and axially moveable with respect thereto; and

iii) a series of compression springs normally biased against one annular surface of the piston to urge said piston toward and against the brake disks to cause said brake disks to brake the output shaft;

an annular fluid pressure cavity defined by another surface of the piston axially-opposite from the one surface to move the piston away from the brake disks when fluid above the force of the springs enters the cavity, said piston including a radially-projecting stop surface across a major portion of the one surface of the piston and the housing including a corresponding radially-projecting stop surface, the stop surface of the piston engaging the stop surface of the housing prior to maximum compression of the springs, wherein the piston is prevented from cocking when the stop surface of the piston contacts the stop surface of the housing, the compression springs provided toward the one end of the housing, the brake disks provided toward the other end of the housing, and the piston disposed axially between the compression springs and the brake disks;

a thrust bearing disposed adjacent the inner end of the output shaft in fluid communication with the hydraulic motor, said thrust bearing disposed between radially-extending and opposing bearing surfaces formed in the housing and in the output shaft, said thrust bearing at least partially axially supporting the inner end portion of said output shaft for rotation relative to the housing;

said housing including a) a unitary, one-piece housing cover at the other end of the housing having a central opening for the output shaft, said housing cover having a cup-shape and receiving and at least partially enclosing the brake disks and the annular piston, and b) a unitary, one-piece housing body toward the one end of the housing having a series of axially-extending cylindrical cavities to receive the compression springs, the cup-shaped housing cover and housing body sealingly enclosing the brake disks, annular piston and compression springs therebetween.

18. The hydraulic device as in claim 17, wherein the stop surface of the piston contacting the stop surface of the housing is at least along the inner diameter of the annular one surface of the piston.

19. The hydraulic device as in claim 18, wherein the stop surface of the piston is also along at least the outer diameter of the one annular surface of the piston.

20. The hydraulic device as in claim 17, wherein the cylindrical cavities for the compression springs open toward the other end of the housing, away from the motor end of the housing.