WO2015181935A1

WO2015181935A1 - Valve device

Info

Publication number: WO2015181935A1
Application number: PCT/JP2014/064340
Authority: WO
Inventors: 一郎鎌田; 石川　哲史; 光正明石; 堀　秀司
Original assignee: 株式会社小松製作所
Priority date: 2014-05-29
Filing date: 2014-05-29
Publication date: 2015-12-03

Abstract

In order to prevent the development of a peak pressure in a downstream hydraulic circuit, a valve device includes: a cylindrical valve main body (310) having, at the center thereof, a main body oil path (311); a slide member (320) provided so as to be slidable relative to the valve main body (310); and a relief spring (340) interposed between the valve main body (310) and the slide member (320) and biasing the slide member (320) to maintain an interrupting position, the slide member (320) being moved from the interrupting position to a communicating position against the biasing force of the relief spring (340) when the oil pressure of the main body oil path (311) has exceeded a pre-set threshold value, wherein a plurality of expansion chambers (310A, 310B, 310C, 310D) are provided in an oil path of the valve main body (310) from a discharge port to an outtake port (351).

Description

Valve device

The present invention relates to a valve device, and more particularly to a valve device suitable as a relief valve used when oil in a hydraulic circuit is discharged.

For work vehicles used as construction machines such as bulldozers, wheel loaders, forklifts, etc., the hydraulic motor is operated by the oil supplied from the hydraulic pump, and the vehicle is driven by rotating the traveling wheel provided on the output shaft of the hydraulic motor. There is what I did.

In a hydraulic circuit applied to this type of work vehicle, the oil in the low-pressure oil passage is discharged to the motor case of the hydraulic motor through the low-pressure selection valve and the relief valve, and further from the motor case to the oil tank through the relief oil passage. While discharging (flushing), the oil in the oil tank is supplied to the low-pressure oil passage by the charge pump, and the hydraulic motor is cooled by leading the oil out of the system (for example, Patent Document 1, (See Patent Document 2 and Patent Document 3). As the relief valve of the hydraulic circuit, for example, the one described in FIG. 12 of Patent Document 4 and the one described in FIG. 1 of Patent Document 5 are generally applied.

JP 2002-227998 A Japanese Patent Laid-Open No. 11-30304 JP 2008-101636 A Japanese Patent Laid-Open No. 2006-22751 JP-A-8-82302

By the way, in the hydraulic circuit described above, it has been confirmed that peak pressure is generated inside the motor case when the work vehicle is shuttle operated, suddenly stopped, or travel stopped. When peak pressure repeatedly occurs in the motor case, the oil seal between the motor case and the output shaft may be damaged, leading to oil leakage.

The relief valve described in Patent Document 5 is configured such that oil after passing through the oil passage of the valve body passes through one expansion chamber. However, with a relief valve configured so that oil that has passed through the oil passage of the valve body simply passes through one expansion chamber, it is difficult to greatly reduce the oil pressure, and peak pressure is generated in the downstream hydraulic circuit. It does not lead to restraining the situation.

In view of the above circumstances, an object of the present invention is to provide a valve device that can more reliably suppress a situation in which a peak pressure is generated in a downstream hydraulic circuit.

In order to achieve the above object, a valve device according to the present invention is slidably disposed in a valve body having an inlet and an outlet, and a body oil passage between the inlet and outlet of the valve body, A slide member that switches between a blocking position that blocks between the introduction port and the outlet port and a communication position that communicates between the introduction port and the outlet port, and is interposed between the valve body and the slide member; Urging means for urging so as to maintain a state where the inlet and the outlet are shut off, and the urging means when the hydraulic pressure of the main body oil passage exceeds a preset threshold value In the valve device configured to move the slide member from the shut-off position to the communication position against the biasing force of the valve body, the valve body is formed with a plurality of expansion chambers in the oil passage on the downstream side of the slide member, And passed through all of the expansion chambers Characterized in that the oil is communicated to the plurality of expansion chambers to derive from the outlet.

Further, the valve device according to the present invention has a cylindrical shape having a main body oil passage at the center, one end of the main body oil passage serves as an introduction port, and has a discharge port on the inner peripheral surface and is guided to the outer peripheral surface. A valve body having an outlet and a cylindrical shape having a valve hole on a peripheral wall, the communication position where the valve hole is opposed to the discharge port of the valve body and the valve hole are closed by the peripheral wall of the valve body A slide member slidably disposed in the main body oil passage of the valve main body in a state of switching to the shut-off position, and interposed between the valve main body and the slide member so that the slide member maintains the shut-off position. Urging means for energizing, and when the oil pressure of the main body oil passage exceeds a preset threshold value, the slide member is moved from the blocking position to the communication position against the urging force of the urging means. In the valve device, the outlet of the valve body A plurality of expansion chambers are formed in the oil passage leading to the outlet, and the plurality of expansion chambers are communicated so as to lead out the oil after passing through all of the expansion chambers from the outlet. Features.

In the valve device according to the present invention, the expansion chamber is formed between an annular recess formed on the outer peripheral surface of the valve main body and a cover member attached to the outer peripheral surface of the valve main body. It is characterized by including space.

Further, the present invention provides the valve device described above, wherein a plurality of the annular spaces are arranged side by side along the axial direction of the valve body, and the annular portion is formed on a wall portion of the valve body located between the plurality of annular spaces. A plurality of throttle holes that communicate with each other are formed.

Further, the present invention is characterized in that, in the valve device described above, the throttle holes are provided in the wall portions located on both sides of the annular space so as to avoid the positions facing each other.

According to the present invention, since the oil pressure is gradually reduced when passing through a plurality of expansion chambers, it is possible to reliably suppress the occurrence of peak pressure in the downstream hydraulic circuit.

1 is a cross-sectional view showing a valve device according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along line XX in FIG. 3 is a cross-sectional view taken along line YY in FIG. FIG. 4 is a hydraulic circuit diagram showing an application example of the valve device shown in FIG. FIG. 5 is a cross-sectional view showing a main part of the valve device according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view showing a main part of a valve device according to Embodiment 3 of the present invention.

Hereinafter, preferred embodiments of a valve device according to the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 shows a valve device according to Embodiment 1 of the present invention, and illustrates a valve device used as a charge relief valve 300 in the hydraulic circuit shown in FIG. The hydraulic circuit in FIG. 4 is for running a work vehicle used as a construction machine such as a bulldozer, and includes an individual hydraulic transmission unit 10 between the engine 1 and the left and right drive wheels 2. Since the hydraulic transmission unit 10 provided for each drive wheel 2 has the same configuration, only one of them will be described below, and the other will be given the same reference numeral and description thereof will be omitted. .

The hydraulic transmission unit 10 is a so-called HST (Hydro-Static Transmission), and includes a hydraulic pump 11 driven by the engine 1 and a traveling hydraulic motor 12 driven by oil supplied from the hydraulic pump 11. And a pair of

main oil passages

13A and 13B constituting a closed circuit for circulating and supplying oil between the hydraulic pump 11 and the hydraulic motor 12.

The hydraulic pump 11 and the hydraulic motor 12 are each a variable displacement type in which the displacement volume is changed by changing the tilt angle of the swash plate or the oblique axis. The hydraulic pump 11 has an input shaft 11 a connected to the output shaft 1 a of the engine 1. The hydraulic motor 12 has an output shaft 12 a connected to the drive wheel 2 of the work vehicle, and can drive the work vehicle by rotating the drive wheel 2. The rotation direction of the hydraulic motor 12 can be changed according to the oil supply direction from the hydraulic pump 11, and the work vehicle can be moved forward or backward. In the following, for the sake of convenience, when distinguishing the pair of

main oil passages

13A and 13B, the one connected to the discharge port located above the hydraulic pump 11 in FIG. 4 is referred to as a “first main oil passage 13A”. 4, the one connected to the discharge port located below the hydraulic pump 11 is referred to as a “second main oil passage 13B”.

The charge unit 20 is attached to the hydraulic transmission unit 10. The charge unit 20 has a charge pump 21 driven by the engine 1, one end connected to the discharge port of the charge pump 21, and the other end via a check valve 23, the first main oil passage 13 A and the second main oil passage 13 A. A charge oil passage 22 branched and connected to each of the oil passages 13B, a tank oil passage 24 extending from the charge oil passage 22 to reach the oil tank T, and a charge safety valve 25 interposed in the tank oil passage 24 It is prepared.

In this charge unit 20, when the engine 1 is driven, the charge pump 21 is always driven. In this state, for example, when the pressure in the first main oil passage 13A or the second main oil passage 13B becomes lower than the set pressure of the charge safety valve 25 due to internal leakage of the hydraulic pump 11 or the hydraulic motor 12, for example. The oil is replenished from the charge pump 21 to one corresponding main oil passage or both

main oil passages

13A, 13B. If the pressures of the first main oil passage 13A and the second main oil passage 13B are both equal to or higher than the set pressure of the charge safety valve 25, the oil discharged from the charge pump 21 will flow through the tank oil passage 24 and the charge safety valve 25. To the oil tank T.

Furthermore, the hydraulic power transmission unit 10 is provided with a flushing unit 30 in the motor case M of the hydraulic motor 12, as shown in FIG. The flushing unit 30 operates according to the differential pressure between the pair of

main oil passages

13A and 13B and selects the low-pressure side

main oil passage

13A or 13B, and the low-pressure side selected by the low-pressure selection valve 31 The

main oil passage

13A or 13B is communicated with the inside of the motor case M, the relief oil passage 33 for connecting the inside of the motor case M to the oil tank T, and the case drain oil passage 32. A charge relief valve 300 is provided.

In this flushing unit 30, when the pressure of the

main oil passage

13A or 13B on the low pressure side selected by the low pressure selection valve 31 is higher than the set pressure of the charge relief valve 300 (<set pressure of the charge safety valve 25). The oil in the low-pressure side

main oil passage

13A or 13B is discharged into the motor case M, and the oil in the motor case M is discharged into the oil tank T through the relief oil passage 33.

In the hydraulic transmission unit 10 configured as described above, when the hydraulic pump 11 is driven by the engine 1, oil is circulated and supplied to the hydraulic motor 12 through the pair of

main oil passages

13A and 13B. The driving wheel 2 is rotationally driven by the above driving, and the work vehicle travels. During this time, the oil flowing through the

main oil passages

13A and 13B is led out of the system and cooled by the operation of the charge unit 20 and the flushing unit 30 described above, and the hydraulic motor 12 is cooled.

Here, when the work vehicle is shuttle operated, suddenly stopped, or travel stopped, the amount of oil discharged to the motor case M is increased by the operation of the flushing unit 30. For example, a peak pressure may be generated, and for example, an oil seal (not shown) between the motor case M and the output shaft 12a may be damaged.

Therefore, in this hydraulic circuit, as shown in FIG. 1, an expansion chamber is provided in the charge relief valve 300, and the pressure of the oil when it is led out by passing through the expansion chamber is reduced to solve the above-described problem. I have to. Hereinafter, a specific configuration of the charge relief valve 300 will be described with reference to FIG.

As shown in FIG. 1, the charge relief valve 300 includes a valve body 310, a slide member 320, and a pilot valve unit 330. The valve main body 310 has a main body oil passage 311 in the center, and one end of the main body oil passage 311 opens as an introduction port 311a, and a support wall 312 has a portion positioned on the other end side of the main body oil passage 311. It has a cylindrical shape. A pilot lead-out hole 313 having a smaller diameter than the main body oil passage 311 is provided at the center of the support wall 312.

The slide member 320 is a cylindrical member that is slidably disposed on one end side of the main body oil passage 311 in the valve main body 310. The slide member 320 is provided with a partition wall 322 at an intermediate portion of the center hole 321 and a plurality of valve holes 323 on a peripheral wall. The partition wall 322 is formed at a position where the center hole 321 of the slide member 320 is substantially divided into two equal parts, and has a pilot introduction hole 324 at the center. The pilot introduction hole 324 is a through hole having a smaller diameter than the pilot lead-out hole 313. The valve hole 323 is formed along the radial direction in a portion of the peripheral wall that is located on one end side of the partition wall 322. In the first embodiment, valve holes 323 are provided at four positions on the same circumference at equal intervals.

The slide member 320 has one end portion provided with a valve hole 323 positioned on the opening side of the main body oil passage 311, and a relief spring (biasing means) 340 interposed between the partition wall 322 and the support wall 312 of the valve main body 310. In this state, the valve body 310 is slidably disposed in the main body oil passage 311. A ring member 341 for preventing the slide member 320 from falling off is fitted to the inner peripheral surface of the main body oil passage 311 on the inlet 311a side. As a result, the slide member 320 is maintained in a state in which the partition wall 322 is most separated from the support wall 312 by the spring force of the relief spring 340 and the one end surface is always in contact with the ring member 341. When an external force is applied to the slide member 320 against the spring force of the relief spring 340, the slide member 320 can be moved in a direction in which the partition wall 322 approaches the support wall 312 with respect to the valve body 310.

The pilot valve unit 330 includes a unit body 331 having a cylindrical shape, a poppet member 332 and a poppet spring 333 housed inside the unit body 331, and the distal end surface of the unit body 331 contacts the support wall 312. The valve body 310 is attached to the other end of the valve body 310 in contact. A pilot communication hole 334 and a plurality of pilot discharge holes 335 are provided at the tip of the unit main body 331. The pilot communication hole 334 is formed from the center hole 339 of the unit main body 331 toward the distal end surface, and communicates with the pilot lead-out hole 313 of the valve main body 310. Although not clearly shown in the figure, a valve seat whose inner diameter gradually increases as it approaches the center hole 339 of the unit main body 331 is formed at the base end of the pilot communication hole 334. The pilot discharge holes 335 are respectively formed along the radial direction from the center hole 339 of the unit main body 331 and open to the outer peripheral surface of the unit main body 331.

The poppet member 332 includes a poppet 332b at the tip of a poppet rod 332a having a thin cylindrical shape. The poppet 332b has a cylindrical shape whose base end portion is larger in diameter than the poppet rod 332a, and has a tapered shape in which the tip portion gradually becomes smaller in diameter toward the tip. The poppet member 332 is movably disposed in the central hole 339 of the unit main body 331 in a state in which the tapered peripheral surface of the poppet 332b can be separated from and connected to the valve seat provided in the pilot communication hole 334 of the unit main body 331. It is. The poppet spring 333 is interposed between the plug member 336 screwed into the base end portion of the unit main body 331 and the poppet 332b of the poppet member 332, and the peripheral surface forming the tapered shape of the poppet 332b is always the valve seat of the pilot communication hole 334. It functions so as to abut on. 1 is an oil filter provided in the pilot communication hole 334.

On the other hand, the charge relief valve 300 is provided with a secondary chamber (discharge port) 310A, a tertiary chamber 310B, a fourth chamber 310C and a fifth chamber 310D as expansion chambers in the valve body 310. The secondary chamber 310 A is an annular space formed between the outer peripheral surface of the slide member 320 by forming an annular recess on the inner peripheral surface of the valve body 310. The secondary chamber 310 A is cut off from the valve hole 323 of the slide member 320 when the one end surface of the slide member 320 is in contact with the ring member 341 (blocking position), while the spring of the relief spring 340. When the slide member 320 is slid in the direction approaching the support wall 312 against the force, it opens to the valve hole 323 of the slide member 320, and the center hole located on one end side of the partition wall 322 in the slide member 320. It is formed so as to communicate with a portion (hereinafter referred to as “primary chamber 321 A”) (communication position).

The tertiary chamber 310 B, the fourth chamber 310 C, and the fifth chamber 310 D are each provided with an annular recess along the axial direction on the outer peripheral surface of the valve body 310, and a cover member 350 is mounted on the outer periphery of the valve body 310. By this, it is the annular space comprised between the cover member 350 and each recessed part. As is apparent from the figure, the tertiary chamber 310B is formed at a position on the outer peripheral side of the secondary chamber 310A, and is secondary through a plurality of 2-3 communication holes 361 provided along the radial direction. It communicates with the chamber 310A. In the first embodiment, 2-3 communication holes 361 that communicate between the secondary chamber 310A and the tertiary chamber 310B are provided at six positions that are equally spaced from each other.

The fourth chamber 310C and the fifth chamber 310D are sequentially arranged in the axial direction of the valve body 310 with respect to the third chamber 310B, and are formed to have a larger volume than the third chamber 310B. A plurality of 3-4 communication holes 362 are provided in the wall portion located between the tertiary chamber 310B and the fourth chamber 310C, and the wall portion located between the fourth chamber 310C and the fifth chamber 310D is provided in the wall portion. A plurality of 4-5 communication holes 363 are provided. The 3-4 communication hole 362 and the 4-5 communication hole 363 are notches opened along the axial direction of the valve main body 310 and on the outer peripheral surface of the valve main body 310, and form a throttle hole with the cover member 350. ing. In the first embodiment, as shown in FIGS. 2 and 3, 3-4 communication holes 362 and 4-5 communication holes 363 are provided at four positions that are equally spaced from each other. The 3-4 communication hole 362 and the 4-5 communication hole 363 are provided at positions shifted from each other by 45 ° in the circumferential direction, and the oil that has passed through the 3-4 communication hole 362 directly reaches the 4-5 communication hole 363. There is nothing.

As shown in FIG. 1, the cover member 350 is a cylindrical member having an inner diameter that can be brought into close contact with the outer peripheral surface of the valve body 310. The cover member 350 has an outer periphery of the valve main body 310 in a state where movement in the axial direction is restricted by a step portion 310 a formed on the outer peripheral surface of the valve main body 310 and a ring member 342 fitted to the outer peripheral surface of the valve main body 310. It is attached to. A plurality of outlets 351 are formed in a portion of the cover member 350 corresponding to the fifth chamber 310D. In the first embodiment, the outlets 351 are provided at 12 positions on the same circumference at equal intervals.

In the charge relief valve 300 having the above-described configuration, the primary chamber 321 A is connected to the outlet of the low pressure selection valve 31 by the case drain oil passage 32, and the outlet 351 provided in the cover member 350 and the pilot valve unit 330. Pilot discharge holes 335 are connected to the inside of the motor case M by case drain oil passages 32, respectively.

Now, when the hydraulic pump 11 is driven, oil is circulated and supplied to the hydraulic motor 12 through the pair of

main oil passages

13A and 13B, and the pressure of the

main oil passage

13A or 13B on the low pressure side selected by the low pressure selection valve 31 is supplied. When the pressure becomes higher than the set pressure of the relief spring 340, the slide member 320 maintained at the blocking position slides, and eventually the slide member 320 shifts to the communication position. During this time, if the pressure in the primary chamber 321A becomes higher than the set pressure of the poppet spring 333, the poppet 332b is separated from the valve seat of the pilot communication hole 334 by the oil that has passed through the pilot introduction hole 324. As a result, oil in the space between the support wall 312 of the valve body 310 and the partition wall 322 of the slide member 320 is discharged from the pilot discharge hole 335 into the motor case M, and the support wall 312 of the valve body 310 and the slide member 320 are discharged. Since the pressure in the space between the first partition wall 322 and the second partition wall 322 decreases, the slide member 320 moves.

When the slide member 320 moves to the communication position, the oil in the primary chamber 321A is discharged to the secondary chamber 310A through the valve hole 323, and the 2-3 communication hole 361, the tertiary chamber 310B, the 3-4 communication hole 362, After sequentially passing through the fourth chamber 310C, the 4-5 communication hole 363, the fifth chamber 310D, and the outlet 351 of the cover member 350, it is discharged into the motor case M through the case drain oil passage 32. Further, the oil in the motor case M is discharged to the oil tank T through the relief oil passage 33.

Here, the oil in the primary chamber 321A expands when it passes through the valve hole 323 and reaches the secondary chamber 310A. Similarly, the oil in the secondary chamber 310A expands when it passes through the 2-3 communication hole 361 and reaches the tertiary chamber 310B, and the oil in the tertiary chamber 310B passes through the 3-4 communication hole 362 and becomes 4 The oil expands when it reaches the next chamber 310C, and the oil in the fourth chamber 310C expands when it reaches the fifth chamber 310D through the 4-5 communication hole 363. Therefore, even when the work vehicle is shuttle operated, suddenly stopped, or travel stopped, the pressure of the oil in the primary chamber 321A is greatly reduced until the oil is discharged into the motor case M. Thus, the generation of the peak pressure in the motor case M can be suppressed, and there is no possibility of damaging an oil seal (not shown) between the motor case M and the output shaft 12a.

In the first embodiment described above, the relief valve 300 in which the secondary chamber 310A, the tertiary chamber 310B, the fourth chamber 310C, and the fifth chamber 310D are provided in the valve body 310 as the expansion chamber is illustrated as an example. The number of chambers is not necessarily limited to this, and may be less than four as long as it is plural, or more than four expansion chambers may be provided as shown in a second embodiment described later. Absent.

(Embodiment 2)
FIG. 5 shows a valve device according to Embodiment 2 of the present invention. The valve device exemplified here is used as the charge relief valve 300 ′ in the hydraulic circuit shown in FIG. 4 as in the first embodiment, and is different from the first embodiment only in the number of expansion chambers.

That is, in the charge relief valve 300 ′ of the second embodiment, the valve body 310 has a secondary chamber (discharge port) 310A, a tertiary chamber 310B, a fourth chamber 310C, a fifth chamber 310D, and a sixth chamber 310E as expansion chambers. It is provided. The configuration of the secondary chamber 310A, the tertiary chamber 310B, the fourth chamber 310C, and the fifth chamber 310D and the 2-3 communication holes 361, 3-4 communication holes 362, and 4-5 communication holes 363 provided between the respective chambers. This configuration is the same as that of the first embodiment, and a sixth chamber 310E is provided on the outer peripheral surface of the valve main body 310 that is further on the proximal side than the fifth chamber 310D. The configuration of the sixth chamber 310E is that the annular recess is formed on the outer peripheral surface of the valve body 310, and the cover member 350 is mounted on the outer periphery of the valve body 310. The same as the fifth chamber 310D. A 5-6 communication hole 364 is provided in a wall portion located between the fifth chamber 310D and the sixth chamber 310E. The 5-6 communication hole 364 and the 4-5 communication hole 363 are provided at positions shifted from each other in the circumferential direction, and the oil that has passed through the 4-5 communication hole 362 does not reach the 5-6 communication hole 364 directly. Absent. Further, the outlet 351 of the cover member 350 is formed only at a portion corresponding to the sixth chamber 310E. Note that the same reference numerals in the second embodiment denote the same components as those in the first embodiment, and a detailed description thereof will be omitted.

Also in this charge relief valve 300 ′, the oil is circulated and supplied to the hydraulic motor 12 through the pair of

main oil passages

13 A and 13 B by the drive of the hydraulic pump 11, and the main pressure on the low pressure side selected by the low pressure selection valve 31. When the pressure in the

oil passage

13A or 13B becomes higher than the set pressure of the relief spring 340, the slide member 320 maintained at the blocking position slides, and eventually the slide member 320 shifts to the communication position.

When the slide member 320 moves to the communication position, the oil in the primary chamber 321A is discharged to the secondary chamber 310A through the valve hole 323, and the 2-3 communication hole 361, the tertiary chamber 310B, the 3-4 communication hole 362, After sequentially passing through the fourth chamber 310C, the 4-5 communication hole 363, the fifth chamber 310D, the 5-6 communication hole 364, the sixth chamber 310E, and the outlet 351 of the cover member 350, the case drain oil passage 32 is passed through. It is discharged into the motor case M. Further, the oil in the motor case M is discharged to the oil tank T through the relief oil passage 33.

Here, the oil in the primary chamber 321A expands when it passes through the valve hole 323 and reaches the secondary chamber 310A. Similarly, the oil in the secondary chamber 310A expands when it passes through the 2-3 communication hole 361 and reaches the tertiary chamber 310B, and the oil in the tertiary chamber 310B passes through the 3-4 communication hole 362 and becomes 4 When the oil reaches the next chamber 310C, the oil in the fourth chamber 310C expands when it reaches the fifth chamber 310D through the 4-5 communication hole 363, and the oil in the fifth chamber 310D reaches 5-6. It expands when it reaches the sixth chamber 310E through the communication hole 364. Therefore, even when the work vehicle is shuttle operated, suddenly stopped, or travel stopped, the pressure of the oil in the primary chamber 321A is greatly reduced until the oil is discharged into the motor case M. Thus, the generation of the peak pressure in the motor case M can be suppressed, and there is no possibility of damaging an oil seal (not shown) between the motor case M and the output shaft 12a.

In the first and second embodiments described above, a pilot-operated relief valve provided with a pilot valve unit is illustrated, but the present invention is not necessarily limited to a pilot-operated valve device. As in the third embodiment, a direct-acting valve device may be used.

(Embodiment 3)
FIG. 6 shows a valve device according to Embodiment 3 of the present invention. The valve device exemplified here is used as a back pressure valve 400 in a hydraulic circuit (not shown), and includes a valve body 410 and a slide member 420. The valve body 410 has a cylindrical shape with a main body oil passage 411 at the center. One end of the main body oil passage 411 opens as an introduction port 411A, and the other end of the main body oil passage 411 is blocked by a closing block 430. Has been. As is apparent from the figure, the other end of the main body oil passage 411 has a larger inner diameter than the one end.

The slide member 420 has a cylindrical shape with a flange 421 at the outer peripheral portion of the other end opened while the tip is closed, and is slidable to the main body oil passage 411 of the valve main body 410 via the tip having a small diameter. Are arranged. The slide position of the slide member 420 toward the distal end side is restricted so that the flange 421 stays at a position retracted from one end surface of the valve body 410 by contacting the inner peripheral step 411a of the body oil passage 411. . Further, a back pressure spring (biasing means) 440 that biases the slide member 420 toward the distal end side with respect to the valve main body 410 is provided between the slide member 420 and the closing block 430.

On the other hand, the valve body 410 is provided with a secondary chamber (discharge port) 410A, a tertiary chamber 410B, a fourth chamber 410C, and a fifth chamber 410D as expansion chambers. The secondary chamber 410 A is an annular space formed between the outer peripheral surface of the slide member 420 by forming an annular recess on the inner peripheral surface of the valve body 410. When the flange 421 of the slide member 420 is in contact with the inner peripheral step 411a of the main body oil passage 411, the secondary chamber 410A is blocked by the slide member 420 (blocking position), while the back pressure spring 440 is used. A portion that opens when the slide member 420 is slid in the direction of approaching the closing block 430 against the spring force of the valve body, and is located on one end side of the slide member 420 in the body oil passage 411 of the valve body 410 (hereinafter referred to as “a”). , “Primary chamber 411A”) (communication position).

The tertiary chamber 410B, the fourth chamber 410C, and the fifth chamber 410D are each provided with annular recesses in parallel along the axial direction on the outer peripheral surface of the valve body 410, and the cover member 450 is mounted on the outer periphery of the valve body 410. By this, it is the annular space comprised between the cover member 450 and each recessed part. As is apparent from the figure, the tertiary chamber 410B is formed at a position on the outer peripheral side of the secondary chamber 410A, and is secondary through a plurality of 2-3 communication holes 461 provided along the radial direction. It communicates with the chamber 410A. In the third embodiment, 2-3 communication holes 461 that communicate between the secondary chamber 410A and the tertiary chamber 410B are provided at six positions that are equally spaced from each other.

The fourth chamber 410C and the fifth chamber 410D are sequentially arranged in the axial direction of the valve body 410 with respect to the third chamber 410B, and are formed to have a larger volume than the third chamber 410B. A plurality of 3-4 communication holes 462 are provided in the wall portion positioned between the tertiary chamber 410B and the fourth chamber 410C, and the wall portion positioned between the fourth chamber 410C and the fifth chamber 410D is provided on the wall portion. A plurality of 4-5 communication holes 463 are provided. The 3-4 communication hole 462 and the 4-5 communication hole 463 are notches opened along the axial direction of the valve main body 410 and on the outer peripheral surface of the valve main body 410, and constitute a throttle hole with the cover member 450. ing. The 3-4 communication hole 462 and the 4-5 communication hole 463 are provided at positions shifted from each other, and the oil that has passed through the 3-4 communication hole 462 does not reach the 4-5 communication hole 463 directly.

The cover member 450 is a cylindrical member having an inner diameter that can be brought into close contact with the outer peripheral surface of the valve body 410. The cover member 450 is configured such that the movement of the valve body 410 in the axial direction is restricted by the outer peripheral step portion 410b formed on the outer peripheral surface of the valve main body 410 and the ring member 442 fitted on the outer peripheral surface of the valve main body 410. It is attached to the outer periphery. A plurality of outlets 451 are formed in a portion of the cover member 450 corresponding to the fifth chamber 410D.

In the back pressure valve 400, when the pressure of the primary chamber 411A in the valve body 410 becomes higher than the set pressure of the back pressure spring 440, the slide member 420 maintained at the shut-off position slides, and the slide member 420 eventually becomes the communication position. Migrate to When the slide member 420 moves to the communication position, the oil in the primary chamber 411A is discharged to the secondary chamber 410A, and the 2-3 communication hole 461, the tertiary chamber 410B, the 3-4 communication hole 462, the fourth chamber 410C, 4 -The gas is discharged from the outlet 451 of the cover member 450 through the fifth communication hole 463 and the fifth chamber 410D. When the slide member 420 is moved to the communication position, oil contained in the slide member 420 is discharged to an oil tank (not shown) through a center hole 430a formed in the closing block 430.

Here, the oil in the primary chamber 411A expands when it reaches the secondary chamber 410A through the valve hole 323. Similarly, the oil in the secondary chamber 410A expands when it passes through the 2-3 communication hole 461 and reaches the tertiary chamber 410B, and the oil in the tertiary chamber 410B passes through the 3-4 communication hole 462 and becomes 4 It expands when it reaches the next chamber 410C, and the oil in the fourth chamber 410C expands when it reaches the fifth chamber 410D through the 4-5 communication hole 463. Accordingly, the pressure of the oil in the primary chamber 411A is greatly reduced until the oil is discharged from the outlet 451 of the cover member 450, and the situation in which the peak pressure is generated in the downstream hydraulic circuit is suppressed. Will be able to.

In the back pressure valve 400 as well, the number of expansion chambers may be less than four or more than four as long as it is plural.

300

Relief valve

310, 410

Valve body

310A,

410A Secondary chamber

310B,

410B Third chamber

310C,

410C Fourth chamber

310D, 410D Fifth chamber

310E Sixth chamber

311, 411 Main

body oil passage

320, 420 Slide member 323 Valve hole 340 Relief springs 350, 450

Cover members

351, 451

Outlet ports

361, 461 2-3 communication holes 362, 462 3-4 communication holes 363, 463 4-5 communication holes 364 5-6 communication holes 400 Back pressure valve 440 Back pressure spring

Claims

A valve body having an inlet and an outlet;
The valve body is slidably disposed in a main body oil passage between the inlet and outlet of the valve body, and the blocking position where the inlet and outlet are blocked is connected to the inlet and outlet. A sliding member that switches to the communication position,
An urging means interposed between the valve body and the slide member and urging so as to maintain a state where the inlet and the outlet are shut off, and the hydraulic pressure of the main body oil passage is set in advance. In the valve device configured to move the slide member from the shut-off position to the communication position against the biasing force of the biasing means when the threshold value is exceeded,
A plurality of expansion chambers are formed in the oil passage on the downstream side of the slide member in the valve body, and the plurality of expansion chambers are led out from the outlet through the oil after passing through all of the expansion chambers. A valve device characterized by communicating with each other.
A valve body having a cylindrical shape with a main body oil passage in the center, one end of the main body oil passage serving as an introduction port, a discharge port on the inner peripheral surface, and a discharge port on the outer peripheral surface;
A cylindrical shape having a valve hole on a peripheral wall, and the valve hole is switched between a communication position facing the discharge port of the valve body and a blocking position where the valve hole is closed by the peripheral wall of the valve body. A slide member slidably disposed in the main body oil passage of the valve body;
And an urging means interposed between the valve body and the slide member to urge the slide member to maintain a shut-off position, and the hydraulic pressure of the body oil passage exceeds a preset threshold value. In the valve device in which the slide member is moved from the blocking position to the communication position against the biasing force of the biasing means in the case,
A plurality of expansion chambers are formed in an oil passage extending from the discharge port to the outlet port of the valve body, and the plurality of expansions are led out from the outlet port after passing through all of the expansion chambers. A valve device characterized by communicating a chamber.
The expansion chamber includes an annular space formed between an annular recess formed in the outer peripheral surface of the valve body and a cover member attached to the outer peripheral surface of the valve body. The valve device described.
A plurality of the annular spaces are arranged side by side along the axial direction of the valve body, and a plurality of throttle holes for communicating the annular spaces with each other are formed in a wall portion of the valve body located between the plurality of annular spaces. The valve device according to claim 3.
The valve device according to claim 4, wherein the throttle holes are provided in the wall portions located on both sides of the annular space so as to avoid positions facing each other.