CA1114718A - Inching valve of the hydraulic balance type - Google Patents
Inching valve of the hydraulic balance typeInfo
- Publication number
- CA1114718A CA1114718A CA335,420A CA335420A CA1114718A CA 1114718 A CA1114718 A CA 1114718A CA 335420 A CA335420 A CA 335420A CA 1114718 A CA1114718 A CA 1114718A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- spool
- valve stem
- hydraulic pressure
- spring
- 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
- 239000012530 fluid Substances 0.000 claims description 7
- 230000000994 depressogenic effect Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000006854 communication Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 241000370092 Actiniopteris Species 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 244000145845 chattering Species 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D25/00—Fluid-actuated clutches
- F16D25/12—Details not specific to one of the before-mentioned types
- F16D25/14—Fluid pressure control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/18—Propelling the vehicle
- B60W30/18009—Propelling the vehicle related to particular drive situations
- B60W30/18063—Creeping
-
- 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
- F16D48/00—External control of clutches
- F16D48/02—Control by fluid pressure
- F16D2048/0209—Control by fluid pressure characterised by fluid valves having control pistons, e.g. spools
-
- 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
- F16D2048/0212—Details of pistons for master or slave cylinders especially adapted for fluid control
-
- 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
- F16D2048/0221—Valves for clutch control systems; Details thereof
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Automation & Control Theory (AREA)
- Transportation (AREA)
- Fluid-Pressure Circuits (AREA)
- Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
- Multiple-Way Valves (AREA)
- Mechanically-Actuated Valves (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An inching valve of the hydraulic balance type com-prising a valve box having a bore hole and a plurality of ports formed therein, a spool slidably mounted within the bore hole, the spool having a spring chamber and a hydraulic pressure receiving chamber formed therein, and a valve stem slidably mounted within the spool, one end of the valve stem is mechanic-ally connected to an inching pedal and the other end being provided with a nut. A spring is accommodated within the spring chamber and a load piston is disposed within the hydraulic pressure receiving chamber. The spring force applied against the valve stem in an axial direction is balanced with the hydraulic pressure exerted on the nut through the load piston in the opposite axial direction.
An inching valve of the hydraulic balance type com-prising a valve box having a bore hole and a plurality of ports formed therein, a spool slidably mounted within the bore hole, the spool having a spring chamber and a hydraulic pressure receiving chamber formed therein, and a valve stem slidably mounted within the spool, one end of the valve stem is mechanic-ally connected to an inching pedal and the other end being provided with a nut. A spring is accommodated within the spring chamber and a load piston is disposed within the hydraulic pressure receiving chamber. The spring force applied against the valve stem in an axial direction is balanced with the hydraulic pressure exerted on the nut through the load piston in the opposite axial direction.
Description
~ ~ 47~L~
INCHING VA~,VE OF THE HYDRAIJLIC BALANCE TYPE
¦ BACKGROUND OF THE INVENTION
I! This invention relates to an inching valve of the hydraulic balance type used in hydraulic circuits o~ the - " construction machinery.
The Japanese Utility Model Publication No. 52-52127 -' discloses an inching valve utilized in a hydraulic circuit for ~, supplying hydraulic fluid to a clutch of a variable speed gear.
, The inching valve includes a valve box having a bore hole and 10an inlet and an outlet ports formed therein, a spool slidably mounted within the bore hole, the spool having a spring chamber and a hydraulic pressure receiving chamber formed therein, and a valve stem slidably mounted within the spool, one end of the . valve stem being mechanïcally connected to an inching pedal.
A spring is accommodated within the spring chamber Il and a load piston is slidably mounted within the hydraulic ;
¦I pressure receiving chamber. Since the hydraulic pressure t exerted on the load piston is absorbed by a collar mounted Il within the bore hole by contacting thereof with a plate slidably 20 1l mounted on the valve stem, this valve stem is not hydraulically ,~
balanced and therefor~ a sharp response and a precise inching control are difficult to obtain.
To improve this problem, a hydraulically balanced -.
.., . . . ~ -,: - ,,.
~L4~
inching valve has been proposed by providing a bypass passage to introduce the hydraulic fluid in the outlet port into a second hydraulic pressure receiving chamber formed between the outer periphery of the valve stem and the wall of the bore hole.
In order to make the valve hydraulically balanced, both the hydraulic pressure receiving chambers must have the-same pressure receiving area. The precise equivalency in the pres-sure receiving area is, however, difficult to obtain due to manufacturing problems.
Further, since the hydraulic fluid in the outlet port is introduced into the first hydraulic pressure receiving chamber through a narrow restriction while it is introduced into the second hydraulic pressure receiving chamber through a relatively large bypass passage, a time-lag`may exist in response time between the two chambers which may sometimes cause a chattering problem.
It is therefore an object of an aspect of the present invention to provide an inching valve of the hydraulic balance type which can overcome the above noted problems.
An object of an aspect of the present invention is to provide an inching valve of the hydraulic balance type which is simple in construction and provides a precise inching control.
In accordance with an aspect of the present inven-tion, there is provided an inching valve of the hydraulic balance type comprising: a valve box having a bore hole form-ed therein, said valve box also having a first, second, third and fourth ports formed therein, the first and the fourth ports being drain ports;
.
.
- `
a ! a spool slidably mounted within said bore hole, said spool ~! `
having a spring chamber formed at one end thereof and a hydrau-lic pressure receiving chamber formed at the other end thereof, said hydraulic fluid receiving chamber being communicated with said third port through a restriction; a valve stem slidably mounted within said spool, said valve stem having a step formed thereon at an intermediate portion thereof, one end of said valve stem being connectible to a manual operating means of said inching valve and the other end being provided with nut means screw-threaded thereon; load piston means slidably mounted on :
said valve stem within said hydraulic pressure receiving chamber, said load piston means being in touch with said nut ; means when hydraulic pressure is introduced into said hydraulic pressure receiving chamber; and spring means accommodated within said spring chamber, one end of said spring means being in touch :.
with the step formed on said valve stem thereby normally urging said spool and said valve to separate from each other wherein the spring force applied against said valve stem in an axial ,j direction is balanced with the hydraulic pressure applied on ~ ~`
j said valve stem through said load piston in the opposite axial :
20 7~ direction.
!l .... -:
. ~ The above and other objects, features and advantages ! of the present invention will be readily apparent from the 'i following description taken in conjunction with the accompanying ~
~¦ drawing. . .
- 3 - . ~:
, .
.. . : . . .... . . .
,, . ' . . ' ' ` ,. .: ' .' . : ... ' ~ : '' .. - .. . .. . :
. .
a li ~
il :
' BRIEF DESCRIPTION OF THE DRAWING
!. - The attached drawing is a cross-sectional view of an inching valve according to the present invention.
, I
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described in detail with reference to the accompanying drawing.
. Reference numeral 2 denotes a valve box having a longitudinal bore hole 4 formed therein. The valve box 2 also has four ports 5, 6, 7 and 8 formed therein. The ports 5 and 8 ' are connected to a reservoir. The port 6 is an inlet port which is connected, for example, to a modulate valve (not shown) while the poTt 7 is an outlet port connected, for example, to a clutch ~ -of a variable speed gear (not shown). Slidably mounted within ~ ;
the bore hole 4 is a spool 10 having a reduced diameter portion 12 at an intermediate part thereof.
The spool 10 has a spring chamber 14 formed at oneend thereof and a hydraulic pressure receiving chamber 16 formed at the other end thereof. A cylindrical wall 18 of the hydrau- -lic pressure receiving chamber 16 has formed therein a restriction ` 20 communicating the port 7 with the hydraulic pressure receiv-ing chamber 16. A plurality of small holes 22 are also formed ', in the cylindrical wall 18.
Slidably inserted within the spool 10 is a valve stem24 having a laTge diameter section 26 and a small diameter i section 28. A stepped portion 30 is formed between the large .
- '' . ' , ' ~ ~', ' ,' ':- , ' -a diameter section 24 and the small diameter section 26. A
compression spring 32 is disposed within the spring chamber 14 with one end being in touch with the stepped portion 30 of the valve stem 24. Thus, the spring 32 normally urges the spool 10 and the valve stem 24 to separate from each other. Disposed within the hydraulic pressure receiving chamber 16 is a load piston 34 with its inner surface being in sliding contact with the small diameter section 28 of the valve stem 24 and its outer surface being in sliding contact with the inner : :
surface of the cyllndrical wall 18. :
Right-hand end 35 of the load piston 34 is brought in contact with a washer 36 mounted around the small diameter section 28 of the valve stem 24 when hydraulic fluid is introduced into the hydraulic pressure receiving chamber 16.
A nut 38 is screw-threaded on the valve stem 24 at right-hand : -, ,.:::
end thereof. A plug 40 having a collar 42 integrally formed therewith is threadably engaged with the valve box 2 at right-hand end thereof to close the bore hole 4. The collar 42 :; .
i functions as a stopper for the spool 10.
. A block 44 is fastened by a plurality of bolts 46 to the left-hand end of the valve box 2 to close the bore hole 4. .
Pivotally connected at 48 to the valve stem 24 is a . link 50 which in turn is pivotable about a pin 52. A rod 54 :
, is provided for interconnecting the link 50 and an inching pedal ~-,l 56. The inching pedal 56 is pivotable about a pin 58 and is - 1, normally urged clockwise by a spring 60. 1 .
¦¦ Th~ link 50 is urged couter-clockwise abcut the pin : .
¦j 52 by a spring 62, thereby normally pushing the valve stem 24 . i, . :
_ 5 : . . ;
1'~ 147ii3 , . .
toward right in the drawing.
i In operation, when the inching pedal 56 is not depressed~ the inching valve remains as it is shown in the drawing. The inlet port 6 is communicated with the outlet port 7 through the reduced diameter portion 12 of the spool 10 thus hydraulic pressure remains same in the both ports. In the ,.
state shown, the spool 10 is urged toward right by the spring 32 but is also urged leftward by the hydraulic pressure introduced into the hydraulic pressure receiving chamber 16 through the restriction 20 from the outlet port 7 and therefore the spool 10 ;
is hydraulically balanced. Similarly, the valve stem 24 is urged toward left ln the drawing by thè spring 32 but is also urged toward right by the hydraulic fluid pressure in the hydraulic pressure receiving chamber 16 because the rightward movement of the load piston 34 is transmitted to the valve - stem 24 ~hrough the washer 36 and the nut 38. Thus the valve stem 24 is also hydraulically balanced.
When the inching pedal 56 is depressed the valve stem 24 is pulled toward left through the rod 54 and the link 50, thus the spring force of the spring 32 is weakened. To compensate this the spool 10 is moved toward left thereby blocking the com-munication between the port 6 and the port 7. Therefore the hydraulic pressure in the port 7 is lowered and the hydraulic , pressure in the chamber 16 is also lowered. As a consequence, " the spool lO is moved rightward by the force of the spring 32, I allowing communication between the port 6 and the port 7. By i' repeating these steps the hydraulic pressure in the port 7 is 1~147i~f set lower than that of the port 6. In short, the hydraulic pressure in the port 7 is reduced in proportion to the amount 'I of depression of the inching pedal 56.
;, When the inching pedal 56 is depressed to its stroke end, the spool 10 is moved leftward to a position where the port 7 is communicated with the drain port 8 through the plurality of small holes 22.
As mentioned hereinabove, since the spring force is balanced by the hydraulic pressure introduced into the single hydraulic pressure receiving chamber 16, the inching valve of -;~: :
,;
~ the present invention can provide a good response to the de-. pression of the inching pedal 56 and hardly produce the so-called chat~ering problem.
Since various changes and modifications of the present invention will occur to and can be made readily by those skilled in the art without departing from the concept and the spirit of ~ .
the invention, the present invention is not to be taken as ~:.
iimited except by the scope of the appended claims. ~ ~
. ',:
, ' ~ --, ~, : . , - . - :
. .
.
INCHING VA~,VE OF THE HYDRAIJLIC BALANCE TYPE
¦ BACKGROUND OF THE INVENTION
I! This invention relates to an inching valve of the hydraulic balance type used in hydraulic circuits o~ the - " construction machinery.
The Japanese Utility Model Publication No. 52-52127 -' discloses an inching valve utilized in a hydraulic circuit for ~, supplying hydraulic fluid to a clutch of a variable speed gear.
, The inching valve includes a valve box having a bore hole and 10an inlet and an outlet ports formed therein, a spool slidably mounted within the bore hole, the spool having a spring chamber and a hydraulic pressure receiving chamber formed therein, and a valve stem slidably mounted within the spool, one end of the . valve stem being mechanïcally connected to an inching pedal.
A spring is accommodated within the spring chamber Il and a load piston is slidably mounted within the hydraulic ;
¦I pressure receiving chamber. Since the hydraulic pressure t exerted on the load piston is absorbed by a collar mounted Il within the bore hole by contacting thereof with a plate slidably 20 1l mounted on the valve stem, this valve stem is not hydraulically ,~
balanced and therefor~ a sharp response and a precise inching control are difficult to obtain.
To improve this problem, a hydraulically balanced -.
.., . . . ~ -,: - ,,.
~L4~
inching valve has been proposed by providing a bypass passage to introduce the hydraulic fluid in the outlet port into a second hydraulic pressure receiving chamber formed between the outer periphery of the valve stem and the wall of the bore hole.
In order to make the valve hydraulically balanced, both the hydraulic pressure receiving chambers must have the-same pressure receiving area. The precise equivalency in the pres-sure receiving area is, however, difficult to obtain due to manufacturing problems.
Further, since the hydraulic fluid in the outlet port is introduced into the first hydraulic pressure receiving chamber through a narrow restriction while it is introduced into the second hydraulic pressure receiving chamber through a relatively large bypass passage, a time-lag`may exist in response time between the two chambers which may sometimes cause a chattering problem.
It is therefore an object of an aspect of the present invention to provide an inching valve of the hydraulic balance type which can overcome the above noted problems.
An object of an aspect of the present invention is to provide an inching valve of the hydraulic balance type which is simple in construction and provides a precise inching control.
In accordance with an aspect of the present inven-tion, there is provided an inching valve of the hydraulic balance type comprising: a valve box having a bore hole form-ed therein, said valve box also having a first, second, third and fourth ports formed therein, the first and the fourth ports being drain ports;
.
.
- `
a ! a spool slidably mounted within said bore hole, said spool ~! `
having a spring chamber formed at one end thereof and a hydrau-lic pressure receiving chamber formed at the other end thereof, said hydraulic fluid receiving chamber being communicated with said third port through a restriction; a valve stem slidably mounted within said spool, said valve stem having a step formed thereon at an intermediate portion thereof, one end of said valve stem being connectible to a manual operating means of said inching valve and the other end being provided with nut means screw-threaded thereon; load piston means slidably mounted on :
said valve stem within said hydraulic pressure receiving chamber, said load piston means being in touch with said nut ; means when hydraulic pressure is introduced into said hydraulic pressure receiving chamber; and spring means accommodated within said spring chamber, one end of said spring means being in touch :.
with the step formed on said valve stem thereby normally urging said spool and said valve to separate from each other wherein the spring force applied against said valve stem in an axial ,j direction is balanced with the hydraulic pressure applied on ~ ~`
j said valve stem through said load piston in the opposite axial :
20 7~ direction.
!l .... -:
. ~ The above and other objects, features and advantages ! of the present invention will be readily apparent from the 'i following description taken in conjunction with the accompanying ~
~¦ drawing. . .
- 3 - . ~:
, .
.. . : . . .... . . .
,, . ' . . ' ' ` ,. .: ' .' . : ... ' ~ : '' .. - .. . .. . :
. .
a li ~
il :
' BRIEF DESCRIPTION OF THE DRAWING
!. - The attached drawing is a cross-sectional view of an inching valve according to the present invention.
, I
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described in detail with reference to the accompanying drawing.
. Reference numeral 2 denotes a valve box having a longitudinal bore hole 4 formed therein. The valve box 2 also has four ports 5, 6, 7 and 8 formed therein. The ports 5 and 8 ' are connected to a reservoir. The port 6 is an inlet port which is connected, for example, to a modulate valve (not shown) while the poTt 7 is an outlet port connected, for example, to a clutch ~ -of a variable speed gear (not shown). Slidably mounted within ~ ;
the bore hole 4 is a spool 10 having a reduced diameter portion 12 at an intermediate part thereof.
The spool 10 has a spring chamber 14 formed at oneend thereof and a hydraulic pressure receiving chamber 16 formed at the other end thereof. A cylindrical wall 18 of the hydrau- -lic pressure receiving chamber 16 has formed therein a restriction ` 20 communicating the port 7 with the hydraulic pressure receiv-ing chamber 16. A plurality of small holes 22 are also formed ', in the cylindrical wall 18.
Slidably inserted within the spool 10 is a valve stem24 having a laTge diameter section 26 and a small diameter i section 28. A stepped portion 30 is formed between the large .
- '' . ' , ' ~ ~', ' ,' ':- , ' -a diameter section 24 and the small diameter section 26. A
compression spring 32 is disposed within the spring chamber 14 with one end being in touch with the stepped portion 30 of the valve stem 24. Thus, the spring 32 normally urges the spool 10 and the valve stem 24 to separate from each other. Disposed within the hydraulic pressure receiving chamber 16 is a load piston 34 with its inner surface being in sliding contact with the small diameter section 28 of the valve stem 24 and its outer surface being in sliding contact with the inner : :
surface of the cyllndrical wall 18. :
Right-hand end 35 of the load piston 34 is brought in contact with a washer 36 mounted around the small diameter section 28 of the valve stem 24 when hydraulic fluid is introduced into the hydraulic pressure receiving chamber 16.
A nut 38 is screw-threaded on the valve stem 24 at right-hand : -, ,.:::
end thereof. A plug 40 having a collar 42 integrally formed therewith is threadably engaged with the valve box 2 at right-hand end thereof to close the bore hole 4. The collar 42 :; .
i functions as a stopper for the spool 10.
. A block 44 is fastened by a plurality of bolts 46 to the left-hand end of the valve box 2 to close the bore hole 4. .
Pivotally connected at 48 to the valve stem 24 is a . link 50 which in turn is pivotable about a pin 52. A rod 54 :
, is provided for interconnecting the link 50 and an inching pedal ~-,l 56. The inching pedal 56 is pivotable about a pin 58 and is - 1, normally urged clockwise by a spring 60. 1 .
¦¦ Th~ link 50 is urged couter-clockwise abcut the pin : .
¦j 52 by a spring 62, thereby normally pushing the valve stem 24 . i, . :
_ 5 : . . ;
1'~ 147ii3 , . .
toward right in the drawing.
i In operation, when the inching pedal 56 is not depressed~ the inching valve remains as it is shown in the drawing. The inlet port 6 is communicated with the outlet port 7 through the reduced diameter portion 12 of the spool 10 thus hydraulic pressure remains same in the both ports. In the ,.
state shown, the spool 10 is urged toward right by the spring 32 but is also urged leftward by the hydraulic pressure introduced into the hydraulic pressure receiving chamber 16 through the restriction 20 from the outlet port 7 and therefore the spool 10 ;
is hydraulically balanced. Similarly, the valve stem 24 is urged toward left ln the drawing by thè spring 32 but is also urged toward right by the hydraulic fluid pressure in the hydraulic pressure receiving chamber 16 because the rightward movement of the load piston 34 is transmitted to the valve - stem 24 ~hrough the washer 36 and the nut 38. Thus the valve stem 24 is also hydraulically balanced.
When the inching pedal 56 is depressed the valve stem 24 is pulled toward left through the rod 54 and the link 50, thus the spring force of the spring 32 is weakened. To compensate this the spool 10 is moved toward left thereby blocking the com-munication between the port 6 and the port 7. Therefore the hydraulic pressure in the port 7 is lowered and the hydraulic , pressure in the chamber 16 is also lowered. As a consequence, " the spool lO is moved rightward by the force of the spring 32, I allowing communication between the port 6 and the port 7. By i' repeating these steps the hydraulic pressure in the port 7 is 1~147i~f set lower than that of the port 6. In short, the hydraulic pressure in the port 7 is reduced in proportion to the amount 'I of depression of the inching pedal 56.
;, When the inching pedal 56 is depressed to its stroke end, the spool 10 is moved leftward to a position where the port 7 is communicated with the drain port 8 through the plurality of small holes 22.
As mentioned hereinabove, since the spring force is balanced by the hydraulic pressure introduced into the single hydraulic pressure receiving chamber 16, the inching valve of -;~: :
,;
~ the present invention can provide a good response to the de-. pression of the inching pedal 56 and hardly produce the so-called chat~ering problem.
Since various changes and modifications of the present invention will occur to and can be made readily by those skilled in the art without departing from the concept and the spirit of ~ .
the invention, the present invention is not to be taken as ~:.
iimited except by the scope of the appended claims. ~ ~
. ',:
, ' ~ --, ~, : . , - . - :
. .
.
Claims (3)
1. An inching valve of the hydraulic balance type comprising:
a valve box having a bore hole formed therein, said valve box also having a first, second, third and fourth ports formed therein, the first and the fourth ports being drain ports;
a spool slidably mounted within said bore hole, said spool having a spring chamber formed at one end thereof and a hydraulic pressure receiving chamber formed at the other end thereof, said hydraulic fluid receiving chamber being communic-ated with said third port through a restriction;
a valve stem slidably mounted within said spool, said valve stem having a step formed thereon at an intermediate portion thereof, one end of said valve stem being connectible to a manual operating means of said inching valve and the other end being provided with nut means screw-threaded thereon;
load piston means slidably mounted on said valve stem within said hydraulic pressure receiving chamber, said load piston means being in touch with said nut means when hydraulic pressure is introduced into said hydraulic pressure receving chamber; and spring means accommodated within said spring chamber, one end of said spring means being in touch with the step formed on said valve stem thereby normally urging said spool and said valve to separate from each other wherein the spring force applied against said valve stem in an axial direction is balanced with the hydraulic pressure applied on said valve stem through said load piston in the opposite axial direction.
a valve box having a bore hole formed therein, said valve box also having a first, second, third and fourth ports formed therein, the first and the fourth ports being drain ports;
a spool slidably mounted within said bore hole, said spool having a spring chamber formed at one end thereof and a hydraulic pressure receiving chamber formed at the other end thereof, said hydraulic fluid receiving chamber being communic-ated with said third port through a restriction;
a valve stem slidably mounted within said spool, said valve stem having a step formed thereon at an intermediate portion thereof, one end of said valve stem being connectible to a manual operating means of said inching valve and the other end being provided with nut means screw-threaded thereon;
load piston means slidably mounted on said valve stem within said hydraulic pressure receiving chamber, said load piston means being in touch with said nut means when hydraulic pressure is introduced into said hydraulic pressure receving chamber; and spring means accommodated within said spring chamber, one end of said spring means being in touch with the step formed on said valve stem thereby normally urging said spool and said valve to separate from each other wherein the spring force applied against said valve stem in an axial direction is balanced with the hydraulic pressure applied on said valve stem through said load piston in the opposite axial direction.
2. An inching valve as claimed in claim 1 wherein said spool has a reduced diameter portion at an intermediate part thereof thereby selectively communicating said second port with said third port.
3. An inching valve as claimed in claim 1 or 2 wherein a plurality of small holes are formed redially in said spool for communicating said third port with said fourth port when said manual operating means is shifted to its stroke end.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP124,377/78 | 1978-09-12 | ||
| JP1978124377U JPS6336161Y2 (en) | 1978-09-12 | 1978-09-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114718A true CA1114718A (en) | 1981-12-22 |
Family
ID=14883886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA335,420A Expired CA1114718A (en) | 1978-09-12 | 1979-09-11 | Inching valve of the hydraulic balance type |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS6336161Y2 (en) |
| CA (1) | CA1114718A (en) |
| FR (1) | FR2436271A1 (en) |
| GB (1) | GB2032062B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0214693Y2 (en) * | 1984-09-29 | 1990-04-20 | ||
| JPS61143915U (en) * | 1985-02-28 | 1986-09-05 | ||
| DE19815889A1 (en) * | 1998-04-08 | 1999-10-14 | Mannesmann Rexroth Ag | Inch brake device |
| CN103527803A (en) * | 2013-10-29 | 2014-01-22 | 合肥今典机械科技有限公司 | End face whole-sealing structure for inching valve |
| US9582007B2 (en) | 2014-08-21 | 2017-02-28 | Louis P. Vickio, Jr. | Pressure regulator |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB781651A (en) * | 1900-01-01 | |||
| GB375537A (en) * | 1931-06-17 | 1932-06-30 | Crosby Valve & Engineering Com | Improvements relating to valves for controlling the flow of fluids |
| GB740631A (en) * | 1953-02-16 | 1955-11-16 | Charles Scott Prendergast | Improvements relating to valves for regulating fluid flow |
| GB801951A (en) * | 1956-05-23 | 1958-09-24 | Jaroco Engineering Co | A fluid-pressure control system for remotely controlling fluid control valves |
| GB885393A (en) * | 1957-07-18 | 1961-12-28 | Zahnradfabrik Friedrichshafen | Improvements in and relating to pressure relief valves |
| GB847679A (en) * | 1957-11-07 | 1960-09-14 | Twin Disc Clutch Co | Hydraulically actuated friction clutch |
| GB974907A (en) * | 1962-05-31 | 1964-11-11 | Davy & United Eng Co Ltd | Fluid regulating valves |
-
1978
- 1978-09-12 JP JP1978124377U patent/JPS6336161Y2/ja not_active Expired
-
1979
- 1979-09-05 GB GB7930705A patent/GB2032062B/en not_active Expired
- 1979-09-10 FR FR7922567A patent/FR2436271A1/en active Granted
- 1979-09-11 CA CA335,420A patent/CA1114718A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2032062A (en) | 1980-04-30 |
| GB2032062B (en) | 1983-01-06 |
| FR2436271A1 (en) | 1980-04-11 |
| JPS5541612U (en) | 1980-03-17 |
| JPS6336161Y2 (en) | 1988-09-26 |
| FR2436271B1 (en) | 1983-03-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |