Kubota K008-3 Workshop Manual page 222

(3)Load check valve function
(7)
(8)
(10)
(10) (7) (9) (8)
(14)
(15)
(11)
(12)
(2g) (2f) (2e) (2d) (2c) (2b) (2a)
Load check valve
(13)
(1) (3) (4) (5) (6)
For smooth movement and easy inching adjustment of
the spool, the passages of the hydraulic source, work-
ing section and tank are all inter connected while the
spool is switched over.
Let's suppose that there is no check valve installed and
taht the working load keeps on forcing the working sec-
tion in the opposite direction. In such situation, the
working section passage, pump passage and tank pas-
sage are all interconnected while the spool is switched
over. This causes a pressure drop and the working load
invites a back flow. This is very hazardous.
With this reason, the check valve is added in halfway
along the working section passage. Even if the passage
pressure drops too low, the woking section's oil is
blocked by the check valve and the working load is
safety maintained.
This function therefore provides for same advantages.
The spool switched over smoothly, and the working
section does not suffer any reverse motion. What's
more, if the spools are activated at once with different-
working section pressure, the oil flows back from the
high-pressure side to the low-pressure one.This design
leads to ease of operation.
(1) Valve body
(2a) Spool
(7) Check valve
(8) Spring
(9) O-ring
(10) Retainer
(11) Cap
(13) Overload relief valve
IV-M-24
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