1. A hydraulic four-wheel-drive working vehicle comprising main and sub driving wheels arranged on one and the other sides in a vehicle lengthwise direction, a main hydraulic motor outputting rotational power for driving the main driving wheel, a sub hydraulic motor outputting rotational power for driving the sub driving wheel, one or plural hydraulic pump operatively driven by a driving power source, a pair of main operation fluid lines fluidly connecting the hydraulic pump and the main hydraulic motor in such a manner that they form a main-driving-wheel HST, and a pair of sub operation fluid lines fluidly connecting the hydraulic pump and the sub hydraulic motor in such a manner that they form a sub-driving-wheel HST, the pair of sub operation fluid lines being independent from the pair of main operation fluid lines, the hydraulic four-wheel-drive working vehicle further comprising
a frontrear differential-lock switch valve that fluidly connects forward-movement high-pressure lines of the pair of main operation fluid lines and the pair of sub operation fluid lines and also fluidly connects the forward-movement low-pressure lines of the pair of main operation fluid lines and the pair of sub operation fluid lines,
wherein the frontrear differential-lock switch valve is configured so as to take a throttling fluid-connection state of fluidly connecting the corresponding lines in a state where a throttle is interposed therebetween and a full fluid-connection state of fluidly connecting the corresponding lines in a state where the throttle is not interposed therebetween.
2. The hydraulic four-wheel-drive working vehicle according to claim 1, further comprising,
a 2-wheel-drive4-wheel-drive switch valve interposed in the pair of sub operation fluid lines so as to divide the pair of sub operation fluid lines into pump-side lines and motor-side lines, the 2-wheel-drive4-wheel-drive switch valve being positioned on a side closer to the sub hydraulic motor than a connecting point at which the pair of sub operation fluid lines are fluidly connected to the pair of main operation fluid lines through the frontrear differential-lock switch valve, and capable of selectively taking an open state or a closed state,
wherein the 2-wheel-drive4-wheel-drive switch valve fluidly connects the corresponding pump-side lines and the motor-side lines of the pair of sub operation fluid lines at the open state, and closes the pump-side lines and fluidly connects one motor-side line and the other motor-side line of the pair of sub operation fluid lines at the closed state.
3. The hydraulic four-wheel-drive working vehicle according to claim 2, wherein the frontrear differential-lock switch valve is set at the full fluid-connection state at the time when the 2-wheel-drive4-wheel-drive switch valve is set at the closed state.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A MEMS transducer, comprising:
a substrate;
a membrane layer, supported by the substrate;
a back-plate layer, supported by the membrane layer, said back-plate layer comprising a respective sidewall portion and a respective raised portion; and
one or more columns separate from the respective sidewall portion of the back-plate layer, said columns connecting the back-plate layer, the membrane layer and the substrate.
2. A MEMS transducer as claimed in claim 1, wherein said columns comprise the back-plate layer.
3. A MEMS transducer as claimed in claim 1, wherein said membrane layer comprises a respective sidewall portion and a respective raised portion.
4. A MEMS transducer as claimed in claim 3, wherein said columns comprise the membrane layer and the back-plate layer.
5. A MEMS transducer as claimed in claim 1, wherein said columns have sloped walls.
6. A MEMS transducer as claimed in claim 1, wherein said columns have stepped walls.
7. A MEMS transducer as claimed in claim 1, wherein said columns are substantially circular.
8. A MEMS transducer as claimed in claim 1, wherein said columns are formed around the periphery of the back-plate layer and the membrane layer.
9. A communications device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in claim 1.
10. A portable telephone device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in claim 1.
11. A portable telephone device as claimed in claim 10, wherein the MEMS transducer is used in a noise-cancellation process.
12. An audio device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in claim 1.
13. An audio device as claimed in claim 12, wherein the MEMS transducer is used in a noise-cancellation process.
14. A computer device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in claim 1.
15. A vehicle comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in-claim 1.
16. A medical device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in any claim 1.
17. An industrial device comprising a micro-electrical-mechanical system (MEMS) transducer as claimed in claim 1.