CA1210666A - Neutral start for hydrostatic transmission - Google Patents
Neutral start for hydrostatic transmissionInfo
- Publication number
- CA1210666A CA1210666A CA000413943A CA413943A CA1210666A CA 1210666 A CA1210666 A CA 1210666A CA 000413943 A CA000413943 A CA 000413943A CA 413943 A CA413943 A CA 413943A CA 1210666 A CA1210666 A CA 1210666A
- Authority
- CA
- Canada
- Prior art keywords
- control ring
- neutral
- concavity
- control
- hydrostatic transmission
- 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.)
- Expired
Links
Landscapes
- Glass Compositions (AREA)
- Control Of Fluid Gearings (AREA)
Abstract
NEUTRAL START FOR HYDROSTATIC TRANSMISSION
Abstract of the Disclosure A hydrostatic transmission including a pump and motor unit wherein the pump unit is displaceable effectuated by an operative member integral to the pump unit. A neutral start switch communicating with a carrying machine is mounted in the pump unit to contact the operative member in a manner causing the neutral start switch to become operative only when the operative member is assuming a neutral position.
Abstract of the Disclosure A hydrostatic transmission including a pump and motor unit wherein the pump unit is displaceable effectuated by an operative member integral to the pump unit. A neutral start switch communicating with a carrying machine is mounted in the pump unit to contact the operative member in a manner causing the neutral start switch to become operative only when the operative member is assuming a neutral position.
Description
NEUTRAL START FOR llYDROSTATIC TRANSMISSION
Background of the Invention This invention relates to radial piston hydros-tatic transmissions and, more particularly, to a means of assuring a neutral transmission settiny.
Radial piston hydrostatic transmissions are commonly used in the smaller variety o~ of~-road vehicles such as small tractors. Unlike a conventional gear transmission which is positive engaging, a radial piston hydrostatic -transmision is continuously engaged. As a result, the transmission control linkage assemble must be able to position a control ring within the hydrostatic transmission with greater precision in order to achieve a true neutral transmission mode. Such control linkage assemblies require frequent adjustment and are incapable of assuring a neutral transmission mode.
Another problem encountered by radial piston hydrostatic transmission occures as a result of control ring creep. Once such transmissions are placed in a functional neutral mode, it is not uncommon for the transmission control ring to creep within the slack range of the control linkage assembly. Control ring creep represents the unintended transmission of power.
Summary~ the Inventio_ It is an objective of the present invention to provide a visual means of determining whether a radial piston hydrostatic transmission is in a neutral mode.
It is a ~urther objective of the present invention to present a means o~ preventing control ring creep.
A conventional radial piston hydrostatic transmission includes a rotor containing a plurality oE radial ball piston.
A control ring is pivotably mounted within the transmission's housing around the rotor and ball pistons. A pivot member actuated by a control lever is seated in the control riny responsible ~or positioning the control ring. A neutral start switch is activated when the control ring enters th~ neutral region and seat within a concavity in the pivot member when the control ring is in the neutral position. The s~itch also functions to resist control ring creep.
4 ~ 1 ~ r~
o ~2~666 Brief De cription of the Drawings FIG. 1 is a sectioned view of a hydrostatic transmission pump and motor units employing radial ball pistons.
FIG. 2 is a sectioned view of -the radial ball fixed displacement piston motor unit.
FIG. 3 is a sectioned view of the radial ball piston hy~rostatic pump unit with a variably displaceable control rin~
and control lever.
Description of the Preferred Embodiment Referring to FIGS. 1, 2 and 3, a conventional radial piston hydrostatic transmission, generally indicated as 11, includes a housing 13 containing a pump unit 15 and motor unit 17 in fluid communication. The pump unit 15 consists of an input shaft 19 driving a rotor 21 containing a plurality of radial ball pistons 230 A control ring 27 is placed around the rotor 21 and pistons 23 pivotably mounted within the housing by pivot pin 2g. The pump unit 15 consists of an output shaft 31 driven by rotor 33 carrying radial ball pistons 35.
The control ring 27 includes a seat 37 occupied by a pivot member 39 in a manner allowing the member 39 to pivot. A
portion of a control lever 41 intrudes into the housing and is rotatably mounted therein by any conventional means. The lever 41 has a linking pin 43 fixably mounted thereto by any conventional means extending into the pivot member 39. It is observed that by rotating the control lever 41 the communication between the linking in 43 and pivot member 39 causes the control ring 27 to pivotally displace about pin 29. A conventional neutral start switch 47 is ~ixably mounted to the housing 13 to extend within the housing having its contact surface 49 in communication with the pivot member 39. The pivot member 39 has formed therein a concavity 51 which receives the contact surface 49 of the neutral start switch 47 when the control ring is in a neutral position, thereby placing the switch 47 in an operative mode. Should the control ring 27 be in a position other than neutral, the contact surface ~9 of switch 47 is in communication with member 39 to place the switch 47 in an inoperative mode~
Further benefit is derived by a forced contract between contact surface 49 and pivot member 39 and the release of the forced contact when surface 49 is received by concavity 51 in that when the surface 49 is received by concavity 51 in that when the ~0
Background of the Invention This invention relates to radial piston hydros-tatic transmissions and, more particularly, to a means of assuring a neutral transmission settiny.
Radial piston hydrostatic transmissions are commonly used in the smaller variety o~ of~-road vehicles such as small tractors. Unlike a conventional gear transmission which is positive engaging, a radial piston hydrostatic -transmision is continuously engaged. As a result, the transmission control linkage assemble must be able to position a control ring within the hydrostatic transmission with greater precision in order to achieve a true neutral transmission mode. Such control linkage assemblies require frequent adjustment and are incapable of assuring a neutral transmission mode.
Another problem encountered by radial piston hydrostatic transmission occures as a result of control ring creep. Once such transmissions are placed in a functional neutral mode, it is not uncommon for the transmission control ring to creep within the slack range of the control linkage assembly. Control ring creep represents the unintended transmission of power.
Summary~ the Inventio_ It is an objective of the present invention to provide a visual means of determining whether a radial piston hydrostatic transmission is in a neutral mode.
It is a ~urther objective of the present invention to present a means o~ preventing control ring creep.
A conventional radial piston hydrostatic transmission includes a rotor containing a plurality oE radial ball piston.
A control ring is pivotably mounted within the transmission's housing around the rotor and ball pistons. A pivot member actuated by a control lever is seated in the control riny responsible ~or positioning the control ring. A neutral start switch is activated when the control ring enters th~ neutral region and seat within a concavity in the pivot member when the control ring is in the neutral position. The s~itch also functions to resist control ring creep.
4 ~ 1 ~ r~
o ~2~666 Brief De cription of the Drawings FIG. 1 is a sectioned view of a hydrostatic transmission pump and motor units employing radial ball pistons.
FIG. 2 is a sectioned view of -the radial ball fixed displacement piston motor unit.
FIG. 3 is a sectioned view of the radial ball piston hy~rostatic pump unit with a variably displaceable control rin~
and control lever.
Description of the Preferred Embodiment Referring to FIGS. 1, 2 and 3, a conventional radial piston hydrostatic transmission, generally indicated as 11, includes a housing 13 containing a pump unit 15 and motor unit 17 in fluid communication. The pump unit 15 consists of an input shaft 19 driving a rotor 21 containing a plurality of radial ball pistons 230 A control ring 27 is placed around the rotor 21 and pistons 23 pivotably mounted within the housing by pivot pin 2g. The pump unit 15 consists of an output shaft 31 driven by rotor 33 carrying radial ball pistons 35.
The control ring 27 includes a seat 37 occupied by a pivot member 39 in a manner allowing the member 39 to pivot. A
portion of a control lever 41 intrudes into the housing and is rotatably mounted therein by any conventional means. The lever 41 has a linking pin 43 fixably mounted thereto by any conventional means extending into the pivot member 39. It is observed that by rotating the control lever 41 the communication between the linking in 43 and pivot member 39 causes the control ring 27 to pivotally displace about pin 29. A conventional neutral start switch 47 is ~ixably mounted to the housing 13 to extend within the housing having its contact surface 49 in communication with the pivot member 39. The pivot member 39 has formed therein a concavity 51 which receives the contact surface 49 of the neutral start switch 47 when the control ring is in a neutral position, thereby placing the switch 47 in an operative mode. Should the control ring 27 be in a position other than neutral, the contact surface ~9 of switch 47 is in communication with member 39 to place the switch 47 in an inoperative mode~
Further benefit is derived by a forced contract between contact surface 49 and pivot member 39 and the release of the forced contact when surface 49 is received by concavity 51 in that when the surface 49 is received by concavity 51 in that when the ~0
- 2 -iL21~66~
1 lrface 49 is received by concavity 51 the transmission 11 is held in neutral to preven-t transmission creep.
The present invention has been described in its preferred embodiment as it relates to a radial hydrostatic transmission.
The $ull scope of the invention should not`be thought as limited by the preferred embodiment and applies to all equivalent embodiments~ The fu].l scope of the present invention is defined by the appended claim.
1 lrface 49 is received by concavity 51 the transmission 11 is held in neutral to preven-t transmission creep.
The present invention has been described in its preferred embodiment as it relates to a radial hydrostatic transmission.
The $ull scope of the invention should not`be thought as limited by the preferred embodiment and applies to all equivalent embodiments~ The fu].l scope of the present invention is defined by the appended claim.
- 3 -
Claims
1. In a radial piston hydrostatic transmission including a pump and motor unit in fluid communication, said pump unit having a rotor carrying a plurality of radial piston balls, a control ring pivotally mounted in a pump housing around said rotor, a member pivotally received in a seat on said control ring, a control shaft rotatably mounted in said pump housing having a transversely extending linking arm slidably received in said member such that rotation of said control shaft causes said control ring to pivot, wherein the improvement comprises means for detecting a neutral location of said control ring and for providing resistance to creep of said control ring in said neutral location, said means including said member having a concavity form on one surface, and a switch having a contact surface matingly sized to said concavity, said contact surface of said switch to be received in said concavity when said control ring occupies said neutral location.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US31481481A | 1981-10-26 | 1981-10-26 | |
| US314,814 | 1981-10-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1210666A true CA1210666A (en) | 1986-09-02 |
Family
ID=23221564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000413943A Expired CA1210666A (en) | 1981-10-26 | 1982-10-21 | Neutral start for hydrostatic transmission |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5884254A (en) |
| CA (1) | CA1210666A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4116725Y1 (en) * | 1964-12-24 | 1966-08-03 |
-
1982
- 1982-10-21 CA CA000413943A patent/CA1210666A/en not_active Expired
- 1982-10-26 JP JP18808382A patent/JPS5884254A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5884254A (en) | 1983-05-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |