Directional and flow control valve and hydraulic system

Patent metadata

Field	Value
Publication number	US-12196337-B2
Application number	US-202118031504-A
Country	US
Kind code	B2
Filing date	Oct 11, 2021
Priority date	Oct 13, 2020
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A directional and flow control valve includes: a housing with a pump port, a first supply/discharge port, a second supply/discharge port, and a tank port, the housing including therein a first pilot chamber, a second pilot chamber, and a third pilot chamber; and a first spool and a second spool, which are independent of each other. The first spool includes a first end surface facing the first pilot chamber and a second end surface facing the third pilot chamber. The second spool includes a first end surface facing the second pilot chamber and a second end surface facing the third pilot chamber. The first spool brings the first supply/discharge port into one of the pump port or the tank port, and the second spool brings the second supply/discharge port into the other one of the pump port or the tank port.

First claim

The invention claimed is:

1. A directional and flow control valve comprising:
a housing with a pump port, a first supply/discharge port, a second supply/discharge port, and a tank port, the housing including therein a first pilot chamber, a second pilot chamber, and a third pilot chamber;
a first spool including a first end surface facing the first pilot chamber and a second end surface facing the third pilot chamber, wherein when the first spool is in a neutral position, the first spool blocks the first supply/discharge port from both the pump port and the tank port, and when the first spool shifts from the neutral position, the first spool brings the first supply/discharge port into direct communication with one of the pump port or the tank port; and
a second spool independent of the first spool, the second spool including a first end surface facing the second pilot chamber and a second end surface facing the third pilot chamber, wherein when the second spool is in a neutral position, the second spool blocks the second supply/discharge port from both the pump port and the tank port, and when the second spool shifts from the neutral position, the second spool brings the second supply/discharge port into direct communication with the other one of the pump port or the tank port.

2. The directional and flow control valve according to claim 1 , wherein
the housing includes a housing body including a through-hole that slidably receives therein the first spool and the second spool, and
the third pilot chamber is a part of an inside of the through-hole between the first spool and the second spool.

3. The directional and flow control valve according to claim 2 , wherein the housing body includes a first flow-in annular groove and a second flow-in annular groove that are positioned at both sides of the third pilot chamber, respectively, and are recessed radially outward from the through-hole, and the first flow-in annular groove and the second flow-in annular groove are connected to the pump port, the first spool includes a land that forms the second end surface of the first spool, and the second spool includes a land that forms the second end surface of the second spool.

4. The directional and flow control valve according to claim 3 , wherein
the housing body includes a first leakage annular groove that is, at a position between the first flow-in annular groove and the third pilot chamber, recessed radially outward from the through-hole, and the first leakage annular groove is connected to the tank port or a drain passage.

5. The directional and flow control valve according to claim 4 , wherein
the housing body includes a second leakage annular groove that is, at a position between the second flow-in annular groove and the third pilot chamber, recessed radially outward from the through-hole, and the second leakage annular groove is connected to the tank port or the drain passage.

6. The directional and flow control valve according to claim 3 , wherein
the housing body includes a second flow-out annular groove, or a second drain annular groove, recessed radially outward from the through-hole and positioned at an opposite side of the second flow-in annular groove from the first flow-in annular groove, the second flow-out annular groove being connected to the tank port, and
the second spool includes a leakage passage that extends from a position, on an outer peripheral surface of the land of the second spool, between the second flow-in annular groove and the second end surface of the second spool to the second flow-out annular groove or the second drain annular groove.

7. The directional and flow control valve according to claim 3 , wherein
the housing body includes either:
a first flow-out annular groove and a second flow-out annular groove that are located at an outer side of the first flow-in annular groove and an outer side of the second flow-in annular groove, respectively, and are recessed radially outward from the through-hole, the first flow-out annular groove and the second flow-out annular groove being connected to the tank port; or
a first drain annular groove and a second drain annular groove that are located at the outer side of the first flow-in annular groove and the outer side of the second flow-in annular groove, respectively, and are recessed radially outward from the through-hole,

the first spool includes a leakage passage that extends from a position, on an outer peripheral surface of the land of the first spool, between the first flow-in annular groove and the second end surface of the first spool to the first flow-out annular groove or the first drain annular groove, and
the second spool includes a leakage passage that extends from a position, on an outer peripheral surface of the land of the second spool, between the second flow-in annular groove and the second end surface of the second spool to the second flow-out annular groove or the second drain annular groove.

8. The directional and flow control valve according to claim 2 , wherein
the housing body includes:
a middle annular groove that is, at a position between the first spool and the second spool, recessed radially outward from the through-hole; and
a pilot passage that is open to the middle annular groove.

9. The directional and flow control valve according to claim 3 , wherein
the housing body includes a pilot passage that is, at a position between the first spool and the second spool, open to the through-hole, and
at least one of a part of the land of the first spool adjacent to the second end surface of the first spool, or a part of the land of the second spool adjacent to the second end surface of the second spool, is reduced in diameter.

10. The directional and flow control valve according to claim 1 , wherein in the first pilot chamber, there is a first spring that applies to the first spool urging force to keep the first spool in a neutral position in which the first spool blocks the first supply/discharge port from both the pump port and the tank port, and in the second pilot chamber, there is a second spring that applies to the second spool urging force to keep the second spool in a neutral position in which the second spool blocks the second supply/discharge port from both the pump port and the tank port.

11. A hydraulic system comprising:
a directional and flow control valve including:
a housing with a pump port, a first supply/discharge port, a second supply/discharge port, and a tank port, the housing including therein a first pilot chamber, a second pilot chamber, and a third pilot chamber;
a first spool including a first end surface facing the first pilot chamber and a second end surface facing the third pilot chamber, wherein the first spool blocks the first supply/discharge port from both the pump port and the tank port, or brings the first supply/discharge port into communication with one of the pump port or the tank port; and
a second spool independent of the first spool, the second spool including a first end surface facing the second pilot chamber and a second end surface facing the third pilot chamber, wherein the second spool blocks the second supply/discharge port from both the pump port and the tank port, or brings the second supply/discharge port into communication with the other one of the pump port or the tank port,
a hydraulic pump connected to the pump port of the directional and flow control valve;
a hydraulic actuator connected to the first supply/discharge port and the second supply/discharge port of the directional and flow control valve, wherein the hydraulic actuator moves in a first direction and a second direction;
a first solenoid proportional valve that adjust

Assignees

• Kawasaki Heavy Ind Ltd

Inventors

• Kondo Akihiro
• Muraoka Hideyasu
• Tode Yoshiyuki

Classifications

• F16K11/22

  with an actuating member for each valve, e.g. interconnected to form multiple-way valves · CPC title

• F16K11/207

  with two handles or actuating mechanisms at opposite sides of the housing · CPC title

• F15B2211/6355

  having valve means · CPC title

• F15B2211/6346

  representing a state of input means, e.g. joystick position · CPC title

• F15B2211/67

  Methods for controlling pilot pressure · CPC title