| 摘要 |
The control valve (11) serves to heat a flow of pressure medium and to keep its temperature constant. The pressure medium is heated by restriction at a spool (22) and if need be at a pilot valve (44) arranged downstream of the spool (22). A thermal sensor (54) controls an electromagnet in such a way that this electromagnet, via its plunger (61), preloads the spring (58) of the pilot valve (44) up to the opening pressure and presses the valve body (43) onto its valve seat (42) if the operating temperature is not yet reached. If this is the case, the pilot valve (44) is opened and the restriction of the pressure medium at the spool (22) is reduced. The pressure medium now flows via a bypass connection (50), as a result of which the flow resistance during neutral circulation is substantially reduced. Rapid relief of the control valve (11) is possible, which also results in lower energy losses and no overstressing of the hydraulic unit. <IMAGE>
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