Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
  • F15B21/04—Special measures taken in connection with the properties of the fluid
  • F15B21/042—Controlling the temperature of the fluid
  • F15B21/0427—Heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
  • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
  • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
  • F15B13/0401—Valve members; Fluid interconnections therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
  • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
  • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
  • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
  • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
  • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
  • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
  • F15B13/08—Assemblies of units, each for the control of a single servomotor only
  • F15B13/0803—Modular units
  • F15B13/0871—Channels for fluid

Definitions

• the present invention relates to a fluid pressure apparatus and a fluid pressure system.
• JP1993-187411A discloses a hydraulic driving device for a hydraulic working machinery including: flow rate control means that controls a discharge flow rate of a variable displacement hydraulic pump; differential pressure detection means that detects a differential pressure between a discharge pressure of the variable displacement hydraulic pump and a load pressure of an actuator; target differential pressure setting means that sets a target value for the differential pressure between the discharge pressure of the hydraulic pump and the load pressure of the actuator as a target differential pressure; and control means that outputs, in accordance with a signal output from the differential pressure detection means, a driving signal to the flow rate control means such that the differential pressure between the discharge pressure of the variable displacement hydraulic pump and the load pressure of the actuator matches the above-described target differential pressure.
• the load pressure of the actuator is guided to the differential pressure detection means as a signal pressure, and a discharge capacity of the pump is controlled on the basis of the signal pressure and a discharge pressure of a pump serving as a self pressure.
• the flow rate of a working fluid in the signal pressure passage is limited so as to be lower than that in a pump passage that guides the self pressure.
• the working fluid in order to ensure operational responsiveness, the working fluid may be warmed by a warm-up operation in which the pump is driven.
• the signal pressure passage is not configured so as to actively cause the flow of the working fluid therein as described above, it is difficult to sufficiently warm the working fluid in the signal pressure passage even if the warm-up operation is performed. Therefore, a difference is caused in the responsiveness between the self pressure and the signal pressure, and as a result, there is a risk in that the responsiveness of a capacity control of the pump is lowered.
• An object of the present invention is to provide a fluid pressure apparatus capable of improving a responsiveness of a capacity control of a pump.
• a fluid pressure apparatus includes a housing provided with a signal pressure passage configured to guide a signal pressure to a variable displacement pump, the variable displacement pump being configured such that a discharge capacity is controlled in accordance with a self pressure discharged by the variable displacement pump and the signal pressure supplied.
• the housing is further provided with: a pump passage configured to guide a working fluid sucked from a tank and discharged by the pump; a tank passage configured to return the working fluid discharged by the pump to the tank; and a communication passage having both ends communicating with the tank passage. At least a potion of the communication passage is arranged adjacent to the signal pressure passage such that the potion is separated from the signal pressure passage only by a wall portion of the housing without any other passage guiding working fluid interposed between the potion and the signal pressure passage.
• a fluid pressure apparatus according to an embodiment of the present invention will be described with reference to the drawings.
• the fluid pressure apparatus is a valve device 100 that controls communication of a pump P and a tank T with a hydraulic cylinder 1 serving as a fluid pressure actuator will be described as an example.
• the valve device 100 switches the supply and discharge of a working oil (a working fluid) to and from the hydraulic cylinder 1, and controls the operation of the hydraulic cylinder 1.
• a working oil a working fluid
• other fluids such as hydraulic water, etc. may also be used as the working fluid.
• valve device 100 and a fluid pressure system 1000 including the same will be described first with reference to FIG. 1 .
• the fluid pressure system 1000 includes: the hydraulic cylinder 1 that is operated by supply and discharge of the working oil serving as the working fluid; the tank T that stores the working oil; the variable displacement pump P that sucks the working oil from the tank T, and pressurizes and discharges the working oil; a control mechanism 110 that controls a discharge capacity of the pump P; and the valve device 100 that controls the flow of the working oil supplied to and discharged from the hydraulic cylinder 1.
• the hydraulic cylinder 1 is a double acting type cylinder having a piston 4 that partitions an interior of a cylinder tube 2 into a rod-side chamber 5 serving as a first fluid pressure chamber and a bottom-side chamber 6 serving as a second fluid pressure chamber.
• a piston rod 3 is connected to the piston 4.
• a tip end of the piston rod 3 is linked to a load (not shown), which is a drive target.
• the working oil is supplied to and discharged from the rod-side chamber 5 of the hydraulic cylinder 1 through a rod-side passage 13.
• the working oil is supplied to and discharged from the bottom-side chamber 6 of the hydraulic cylinder 1 through a bottom-side passage 14.
• the hydraulic cylinder 1 is extended as the working oil is supplied to the bottom-side chamber 6 and the working oil is discharged from the rod-side chamber 5. Conversely, the hydraulic cylinder 1 is contracted as the working oil is supplied to the rod-side chamber 5 and the working oil is discharged from the bottom-side chamber 6.
• the pump P is a variable displacement piston pump whose discharge capacity is changed according to the tilt angle of a swash plate (not shown).
• the pump P may be of other type, such as a variable displacement vane pump, etc., for example.
• the discharge capacity of the pump P is controlled by the control mechanism 110 on the basis of a differential pressure between a self pressure Pps, which is the pressure of the working oil discharged by the pump P itself, and a load pressure Pls of the hydraulic cylinder 1 serving as a signal pressure.
• the control mechanism 110 has: a regulator 111 to which the self pressure Pps and the load pressure Pls are respectively guided and which generates a control pressure Pc according to the differential pressure between the self pressure Pps and the load pressure Pls; and a control actuator 112 that controls the discharge capacity by driving the swash plate of the pump P in accordance with the control pressure Pc guided from the regulator 111.
• the control actuator 112 is a single-acting type hydraulic cylinder that is extended and contracted in accordance with the supplied control pressure Pc, for example. By driving the control actuator 112 in accordance with the control pressure Pc based on the differential pressure between the self pressure Pps and the load pressure Pls, the discharge capacity of the pump P is controlled such that the differential pressure between the self pressure Pps and the load pressure Pls remains constant.
• the valve device 100 includes: a control valve 20 that controls the flow of the working oil supplied to and discharged from the hydraulic cylinder 1; a pump passage 11 through which the working oil discharged by the pump P is guided; a tank passage 12 that guides the working oil discharged by the pump P and returned to the tank T; the rod-side passage 13 that communicates with the rod-side chamber 5; the bottom-side passage 14 that communicates with the bottom-side chamber 6; a load pressure passage 15 serving as the signal pressure passage that guides the load pressure Pls serving as the signal pressure; a communication passage 17 that communicates with the tank passage 12 at its both ends; a relief valve 30 that is opened when the self pressure Pps (the discharge pressure) of the pump P reaches a predetermined relief pressure and allows the working oil discharged from the pump P to return to the tank T; and an unloading valve 40 that relieves the self pressure Pps (the discharge pressure) of the pump P to the tank T in accordance with the differential pressure between the self pressure Pps and the load pressure Pls.
• the pump passage 11, the tank passage 12, the rod-side passage 13, the bottom-side passage 14, and the load pressure passage 15 are connected to the control valve 20.
• the control valve 20 is a spool valve whose position is switched as a spool (not shown) is moved in accordance with the pilot pressure respectively supplied to pilot chambers 21a and 21b and the biasing force exerted by springs 22a and 22b each serving as a biasing member.
• the control valve 20 has a contracting position 20A at which the hydraulic cylinder 1 is contracted, an extending position 20B at which the hydraulic cylinder 1 is extended, and a neutral position 20C at which the working oil is not supplied to and discharged from the hydraulic cylinder 1.
• the control valve 20 When the pilot pressure is supplied to the first pilot chamber 21a, the control valve 20 is set to the contracting position 20A (the state shown in FIG. 1 ).
• the pump passage 11 communicates with the rod-side passage 13 and the load pressure passage 15 via a restrictor 23, and the bottom-side passage 14 communicates with the tank passage 12.
• the working oil is supplied to the rod-side chamber 5 and the working oil is discharged from the bottom-side chamber 6, and thus, the hydraulic cylinder 1 is contracted.
• the control valve 20 When the pilot pressure is supplied to the second pilot chamber 21b, the control valve 20 is set to the extending position 20B. At the extending position 20B, the pump passage 11 communicates with the bottom-side passage 14 and the load pressure passage 15 via the restrictor 23, and the rod-side passage 13 communicates with the tank passage 12. As a result, the working oil is supplied to the bottom-side chamber 6 and the working oil is discharged from the rod-side chamber 5, and thus, the hydraulic cylinder 1 is extended.
• the control valve 20 In a state in which the pilot pressure is not supplied to any of the pilot chambers 21a and 21b, the control valve 20 is set to the neutral position 20C by the biasing force exerted by the springs 22a and 22b. At the neutral position 20C, the respective communications of the pump passage 11 and the tank passage 12 with the rod-side passage 13 and the bottom-side passage 14 are shut off, and the pump passage 11 and the load pressure passage 15 are communicated with the tank passage 12.
• the pressure is guided to the load pressure passage 15 at the same level as the working oil discharged by the pump P and supplied to the hydraulic cylinder 1 via the restrictor 23, which is provided on the control valve 20.
• the pressure of the working oil in the load pressure passage 15 is guided to the regulator 111 as the load pressure Pls.
• the pressure of the working oil in the pump passage 11, which has been discharged by the pump P and which is guided to the control valve 20, is guided to the regulator 111 as the self pressure Pps.
• the load pressure passage 15 communicates with the tank passage 12 via a restrictor 50.
• Both ends of the communication passage 17 communicate with the tank passage 12, and the working oil in the tank passage 12 is guided to the communication passage 17. Any other passages are not connected to the communication passage 17. In addition, no hydraulic equipment, such as a valve, etc. is also provided on the communication passage 17. In other words, the working oil in the tank passage 12 is only guided to the communication passage 17, and the communication passage 17 does not affect the function of the valve device 100 that controls the flow of the working oil, and so, the communication passage 17 is a passage that merely bypasses the tank passage 12 by being branched from the tank passage 12 and joined with the tank passage 12.
• the relief valve 30 is provided in a relief passage 18 through which the pump passage 11 and the tank passage 12 are communicated.
• the relief valve 30 is opened when the pressure in the pump passage 11 reaches a predetermined relief pressure, and thereby, the working oil discharged by the pump P is allowed to flow into the tank T.
• the unloading valve 40 is provided in an unload passage 19 that communicates with the pump passage 11 and the tank passage 12.
• the unloading valve 40 is opened when the differential pressure between the self pressure Pps of the pump P and the load pressure Pls reaches a predetermined valve opening pressure, and thereby, the working oil discharged by the pump P is allowed to flow into the tank T.
• valve device 100 and the communication passage 17 will be described with reference to FIGs. 2 to 4 .
• the valve device 100 is formed of a plurality of valve blocks 101 (in this embodiment, five valve blocks) that are connected in a predetermined direction (the up-down direction in FIG. 2 ).
• Each of the valve blocks 101 has an independent housing 10, and the valve device 100 is integrally formed by connecting the housings 10 by means of bolts (not shown), etc.
• the communication passage 17 is provided in one valve block 101a, among the valve blocks 101, which is sandwiched between a pair of valve blocks 101b and 101c.
• the valve block 101a in which the communication passage 17 is provided, is connected to other valve blocks 101b and 101c on both sides in the connecting direction of the valve blocks 101.
• the “housing 10" refers to the housing 10 of the valve block 101a, in which the communication passage 17 is provided.
• the housing 10 accommodates a pair of unloading valves 40.
• One of the pair of unloading valves 40 is in another circuit system, other than the circuit system shown in FIG. 1 , provided in the fluid pressure system 1000. Because the pair of unloading valves 40 have the similar configurations with each other, the configuration of the one unloading valve 40 will be explained below as an example, and the explanation of the other unloading valve 40 will be omitted as appropriate.
• the housing 10 includes: a bottomed accommodating hole 40a that accommodates a spool 41 of the unloading valve 40; the pump passage 11 that opens to the accommodating hole 40a; the tank passage 12 that opens to the accommodating hole 40a; and the load pressure passage 15 that opens to the accommodating hole 40a.
• the tank passage 12 has: a first tank passage 12a that communicates with the respective accommodating holes 40a of the pair of unloading valves 40; a second tank passage 12b that communicates with the first tank passage 12a and extends in the connecting direction of the valve blocks 101 (in the direction orthogonal to the plane of the drawing in FIG. 3 ); and recessed portions 10a that are respectively provided on two mating surfaces 10b and 10c that are in contact with adjacent two other valve blocks 101b and 101c (see FIG. 4 ).
• the second tank passage 12b communicates with the respective recessed portions 10a in the two mating surfaces 10b and 10c.
• the recessed portions 10a respectively open in the mating surfaces 10b and 10c.
• the tank passage 12 communicates with the tank passages 12 that are formed in the other valve blocks 101 via the recessed portions 10a in the mating surfaces 10b and 10c. Because the mating surfaces 10b and 10c to the adjacent two other valve blocks 101b and 101c have the same configuration with each other, the illustration of the mating surface 10c and the recessed portion 10a to the valve block 101c will be omitted.
• the load pressure passage 15 has: a first load pressure passage 15a that is provided so as to extend substantially perpendicularly to the center axis of the accommodating hole 40a (the spool 41) and opens to the accommodating hole 40a; and a second load pressure passage 15b that is provided so as to extend along the center axis of the accommodating hole 40a and communicates with the first load pressure passage 15a.
• the first load pressure passage 15a and the second load pressure passage 15b are each a circular hole having a circular cross section. Note that a portion of a load pressure passage 15b that opens to the accommodating hole 40a of the other unloading valve 40 is provided on a cross section different from the cross section shown in FIG. 3 .
• This other load pressure passage 15b extends in the direction orthogonal to the plane of the drawing from the cross section different from the cross section shown in FIG. 3 towards the cross section shown in FIG. 3 , and opens to an end surface of the housing 10 on the same cross section as the one load pressure passage 15a (on the cross section shown in FIG. 3 ).
• the portion provided on the cross section different from the cross section shown in FIG. 3 is shown by broken lines.
• the unloading valve 40 has the spool 41 that is movably inserted into the accommodating hole 40a, an unload spring 45 serving as the biasing member that biases the spool 41 towards a bottom portion of the accommodating hole 40a, and a cap 46 that closes the accommodating hole 40a.
• a self-pressure chamber 47 into which the self pressure Pps is guided, is formed between one end portion of the spool 41 and the bottom portion of the accommodating hole 40a.
• a load pressure chamber 48 into which the load pressure Pls is guided, is formed between other end portion of the spool 41 and the cap 46.
• the unload spring 45 is provided so as to act against the biasing force exerted by the pressure in the self-pressure chamber 47.
• the spool 41 is moved within the accommodating hole 40a such that the motive force caused by the pressure in the load pressure chamber 48, the motive force caused by the pressure in the self-pressure chamber 47, and the biasing force exerted by the unload spring 45 are balanced.
• the spool 41 is formed with: a first self-pressure introducing passage 42a that is formed so as to extend along the axial direction of the spool 41 and that constantly communicates with the self-pressure chamber 47; and a second self-pressure introducing passage 42b that opens at an outer circumferential surface of the spool 41 and communicates with the first self-pressure introducing passage 42a.
• the second self-pressure introducing passage 42b is formed so as to be constantly in communication with the pump passage 11 opening to the accommodating hole 40a, regardless of the position of the spool 41. Thus, the self pressure Pps is always guided to the self-pressure chamber 47 from the pump passage 11.
• the spool 41 is formed with: a first load-pressure introducing passage 43a that is formed so as to extend along the axial direction of the spool 41 and that constantly communicates with the load pressure chamber 48; and a second load-pressure introducing passage 43b that opens at the outer circumferential surface of the spool 41 and communicates with the first load-pressure introducing passage 43a.
• the second load-pressure introducing passage 43b is formed so as to be constantly in communication with the load pressure passage 15 opening to the accommodating hole 40a, regardless of the position of the spool 41.
• the load pressure Pls is always guided to the load pressure chamber 48 from the load pressure passage 15.
• annular communication groove 44 is formed for controlling the communication between the tank passage 12 and the pump passage 11 in accordance with the position of the spool 41.
• the spool 41 abuts against the bottom portion of the accommodating hole 40a, and the unloading valve 40 is in a closed state (the state shown in FIG. 3 ). In a state in which the unloading valve 40 is closed, the communication between the pump passage 11 and the tank passage 12 through the accommodating hole 40a is shut off by the spool 41.
• the housing 10 is formed with a pair of communication passages 17a and 17b.
• Each of the communication passages 17a and 17b is formed solely by a single through-hole that extends linearly along the connecting direction of the valve blocks 101.
• Each through-hole opens at both of the mating surfaces 10b and 10c to other valve blocks 101 of the housing 10 by communicating with the recessed portions 10a.
• the communication passages 17a and 17b communicate with the tank passage 12 by respectively having both ends communicating with the recessed portion 10a.
• the one communication passage 17a is provided in the hydraulic circuit system shown in FIG. 1 .
• the other communication passage 17b is provided in another hydraulic circuit system in which the other unloading valve 40 is provided. Because the configurations of the pair of communication passages 17a and 17b are the same with each other, in the following, only the detailed explanation of the communication passage 17a in the hydraulic circuit system shown in FIG. 1 will be provided, and the explanation of the other communication passage 17b will be omitted.
• a portion of the communication passage 17a is located adjacent to the first load pressure passage 15a of the load pressure passage 15 such that the portion is separated from the first load pressure passage 15a only by a wall portion of the housing 10 without any other passage for guiding the working oil interposed therebetween.
• the portion where the first load pressure passage 15a and the communication passage 17a intersect in the portion where the first load pressure passage 15a and the communication passage 17a intersect (the portion B with cross-hatching in FIG.
• the imaginary line connecting the center axis of the first load pressure passage 15a and the center axis of the communication passage 17 in the shortest distance does not intersect with any other passage or hydraulic equipment and only intersect with the wall portion of the housing 10.
• valve device 100 In the following, operational advantages of the valve device 100 will be described.
• the load pressure passage is provided to guide the load pressure serving as the signal pressure
• the load pressure passage is configured so as to communicate with the tank passage via the restrictor and such that the flow amount returned to the tank is relatively limited, making the pressure less likely to be decreased.
• the flow of the working oil is relatively limited in the load pressure passage. Therefore, the working oil that has been warmed by the warming-up operation is less likely to be guided to the load pressure passage.
• the communication passage 17a in which the internal working oil flowing therein has been warmed, is arranged adjacent to the load pressure passage 15 such that the communication passage 17a and the load pressure passage 15 are separated only by the wall portion of the housing 10 without any other passage interposed therebetween.
• the temperature of the working oil in the communication passage 17a is transferred to the working oil in the load pressure passage 15 via the wall portion of the housing 10, and thereby, the working oil in the load pressure passage 15 is warmed.
• the cause of the temperature difference between the working oil at the self pressure Pps and the working oil at the load pressure Pls is suppressed, and it is possible to improve the responsiveness for the capacity control of the pump P.
• the communication passage 17a may be formed such that the portion thereof adjacent to the load pressure passage 15 is formed closer to the load pressure passage 15 to an extent that durability can be ensured.
• the communication passage 17a may be arranged such that the portion thereof adjacent to the load pressure passage 15 may also be spaced from the load pressure passage 15 to an extent that allows the working oil in the load pressure passage 15 to be warmed.
• the communication passage 17a only bypasses the tank passage 12 and has no effect on the function of the valve device 100. In other words, according to the this embodiment, it is possible to increase the temperature of the working oil in the load pressure passage 15 without affecting the function of the valve device 100.
• the communication passage 17a is formed solely by a single straight through-hole whose both ends respectively open at the mating surfaces 10b and 10c of the valve block 101. With such a configuration, it is possible to form the communication passage 17a with ease.
• the communication passage 17 is provided in the valve block 101a, in which the unloading valve 40 is provided, in the valve device 100 for controlling the communication of the hydraulic cylinder 1 with the pump P and the tank T.
• the communication passage 17 may be provided in the control mechanism 110 for controlling the discharge capacity of the pump P.
• the communication passage 17 may also be provided in the regulator 111 or the control actuator 112.
• a housing (not shown) of the control mechanism 110 may be separate from or integral with a pump housing of the pump P or the housing 10 of the valve device 100.
• the fluid pressure apparatus may be the control mechanism 110 (the regulator 111 or the control actuator 112) that controls the discharge capacity of the pump P.
• control mechanism 110 may be configured such that the regulator 111 is not included and such that the self pressure Pps of the pump P and the load pressure Pls of the hydraulic cylinder 1 are guided directly to the control actuator 112, and the control actuator 112 is driven directly by the differential pressure between the self pressure Pps and the load pressure Pls.
• the communication passage 17 is a single through-hole that opens at the mating surfaces 10b and 10c of the housing 10.
• the communication passage 17 may be configured of a plurality of holes, and the communication passage 17 may also be configured to communicate with the tank passage 12 at places other than the recessed portions 10a in the mating surfaces 10b and 10c.
• the communication passage 17 is provided in the one valve block 101a having the other valve blocks 101b and 101c on its both sides in the connecting direction.
• the valve device 100 has three valve blocks 101, namely, the valve block 101a, in which the communication passage 17 is provided, and two valve blocks 101b and 101c that are adjacent to the valve block 101a on both sides thereof in the connecting direction.
• other valve blocks 101 may further be connected to these three valve blocks 101a, 101b, and 101c.
• the communication passage 17 may be provided in the valve block 101 that is provided at the end in the connecting direction.
• the communication passage 17 may be provided in the valve device 100 that is formed of two valve blocks 101 or a single valve block 101 (monoblock). In other words, the number of the valve blocks 101 can be any number.
• the fluid pressure system 1000 includes the variable displacement pump P and the valve device 100 serving as the fluid pressure apparatus.
• the valve device 100 includes the housing 10 including the load pressure passage 15 configured to guide the load pressure Pls to the variable displacement pump P, the variable displacement pump P being configured such that the discharge capacity is controlled in accordance with the self pressure Pps discharged by the variable displacement pump P and the load pressure Pls supplied, wherein the housing 10 further includes: the pump passage 11 configured to guide the working oil sucked from the tank T and discharged by the pump P; the tank passage 12 configured to return the working oil discharged by the pump P to the tank T; and the communication passage 17 having both ends communicating with the tank passage 12, and wherein at least a potion of the communication passage 17 is arranged adjacent to the load pressure passage 15 such that the portion is separated from the load pressure passage 15 only by the wall portion of the housing 10 without any other passage guiding the working oil interposed between the portion and the load pressure passage 15.
• the working oil which is guided to the tank passage 12 by being sucked from the tank T and discharged by the pump P, is warmed by the warming-up operation. Therefore, the working fluid in the communication passage 17, which communicates with the tank passage 12, also becomes a warmed working oil. Because at least a potion of the communication passage 17 is arranged adjacent to the load pressure passage 15 with no other passage provided between them, at the adjacent portion, the heat of the working oil in the communication passage 17 is transferred to the load pressure passage 15. Thus, it is possible to warm the working oil in the load pressure passage 15. Therefore, it is possible to improve the responsiveness of the capacity control of the pump P.
• valve device 100 controls the communication of the pump P and the tank T with the hydraulic cylinder 1 and has three valve blocks 101 that are connected to in a predetermined direction.
• the valve blocks 101 each has the independent housing 10.
• the communication passage 17, in the one valve block 101a has the through-hole, the through-hole opening at each of the mating surfaces 10b and 10c to the housings 10 of the two valve blocks 101b and 101c, both of which are adjacent to the one valve block 101a.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fluid-Pressure Circuits (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Valve Housings (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=90477100

Family Applications (1)

Country Status (3)

Family Cites Families (4)

• 2022
  • 2022-09-30 JP JP2022158429A patent/JP2024052002A/ja active Pending
• 2023
  • 2023-07-19 WO PCT/JP2023/026371 patent/WO2024070149A1/ja not_active Ceased
  • 2023-07-19 EP EP23871393.7A patent/EP4596898A1/de active Pending

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