JP2005076857A - Pressure regulating valve, hydraulic coupling device equipped with the pressure regulating valve, and power transmission device for a four-wheel drive vehicle equipped with the hydraulic coupling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent "squeezing" or the like in a moving body in a moving body accommodating space formed in a plate member even when the centering of two joined plate members is insufficient.
A right valve hole m2 formed extending in the thickness direction of a right inner side plate 32R and a left valve hole m4 formed extending in a thickness direction of a left inner side plate 32L are coaxially joined. A communicating hole as an adjustment pressure supply oil passage formed in the right inner side plate 32R when the moving body has a moving body in the moving body containing space m1 and the moving body moves in the moving body containing space m1. In the first relief valve RV1 configured such that the communication between the h9R and the communication groove g2R as the relief oil passage is performed and shut off, the moving body includes the first member B1 positioned on the right valve hole m2 side and the left valve hole m4. It is comprised from two members with the 2nd member C1 located in the side.
[Selection] FIG.

Description

  The present invention relates to a pressure regulating valve configured by providing a moving body for opening and closing an oil passage in a moving body accommodation space formed between two joined plate members. The present invention also relates to a hydraulic coupling device configured with such a pressure regulating valve, and further to a power transmission device for a four-wheel drive vehicle configured with the hydraulic coupling device.

  Conventionally, as one form of a power transmission device provided in a four-wheel drive vehicle, engine driving force is directly transmitted to left and right main drive wheels (for example, left and right front wheels), while left and right sub drive wheels (for example, left and right drive wheels) A configuration is known in which power is transmitted to the rear wheels via a hydraulic coupling device. This hydraulic coupling device is a fluid transmission device having a pair of left and right vane pumps inside a casing, and the axles of left and right auxiliary drive wheels are connected to the rotors of both vane pumps. The casing is rotationally driven around the axle by a propeller shaft to which power from the engine is transmitted, and rotates integrally with the cam ring of each vane pump. The discharge port and suction port of each vane pump, and the discharge ports and suction ports of both vane pumps communicate with each other through an oil passage, and an orifice for generating a load on the vane pump is provided in the middle of these oil passages (for example, See the following patent document).

When a pressure regulating valve such as a relief valve for pressure adjustment is provided between the oil chambers of the two vane pumps constituting such a hydraulic coupling device, the movement provided to extend over both side plates of the joined vane pumps. A moving body such as a spool is inserted in the body housing space. The assembly of the pressure regulating valve having such a configuration is possible because it is only necessary to insert the moving body (and the spring member that urges the moving body) into the moving body accommodating space and then join both side plates. There is an advantage that the process becomes very simple.
Japanese Patent Laid-Open No. 7-125555

  However, in the pressure regulating valve configured as described above, when the two plate members (side plates) are joined with sufficient accuracy without being centered, the shaft is displaced between the valve holes provided in both plate members. (Center axis misalignment) occurs, and the moving body that moves in the moving body accommodating space formed by these valve holes receives a lateral force from the plate member side, and so-called "squeezing" occurs, and moves while the valve is in use. There was a problem that it was easy for problems such as the body to stop moving.

  The present invention has been made in view of such a problem, and even if the centering of two joined plate members is insufficient, the movement in the moving body accommodating space formed in the plate member is achieved. An object of the present invention is to provide a pressure regulating valve having a configuration that does not cause “squeezing” to the body. Another object of the present invention is to provide a hydraulic coupling device configured using such a pressure regulating valve, and a power transmission device for a four-wheel drive vehicle configured using the hydraulic coupling device. It is said.

  The pressure regulating valve according to the present invention includes a joined first plate member (for example, the right inner side plate 32R in the embodiment), a second plate member (for example, the left inner side plate 32L in the embodiment), and the first plate. A first valve hole (for example, the right valve hole m2 in the embodiment) formed extending in the thickness direction of the member and a second valve hole (for example, the embodiment) formed extending in the thickness direction of the second plate member. And the left valve hole m4) in the movable body accommodating space formed by being coaxially joined to each other, and the movable body moves in the movable body accommodating space, whereby the first plate Communication between the regulated pressure supply oil passage (for example, the communication hole h9R in the embodiment) formed in the member and the relief oil passage (for example, the communication groove g2R in the embodiment) and blocking thereof In a pressure regulating valve having a configuration to be performed (for example, the first relief valve RV1 in the embodiment), the moving body includes a first member located on the first valve hole side and a second member located on the second valve hole side. It is comprised from two members.

  Here, in the pressure regulating valve according to the present invention, the adjustment pressure supply oil passage extends coaxially with the central axis of the first valve hole, and the relief oil passage is substantially orthogonal to the central axis of the first valve hole. A tapered valve seat that extends toward the second plate member is formed at the connecting portion between the adjustment pressure supply oil passage and the first valve hole, and the first member is adjusted while being pressed against the valve seat. It is preferable that the configuration is a spherical member having an outer diameter that can block communication between the pressure supply oil passage and the relief oil passage. Further, in the pressure regulating valve having such a configuration, the inner diameter of the minimum inner diameter portion in the second valve hole is formed smaller than the inner diameter of the first valve hole, and the second member has the minimum inner diameter portion in the second valve hole. It is preferable that it is composed of a rod-shaped member having an outer diameter slightly smaller than the inner diameter. Further, a back pressure supply oil passage connected to the second valve hole is formed in the second plate member, and the second member receives the pressure in the back pressure supply oil passage and always attaches the first member to the valve seat side. It is preferable that the communication between the back pressure supply oil passage and the second valve hole is always cut off. Still further, the first member is urged in a direction that blocks the communication between the regulated pressure supply oil passage and the relief oil passage by a spring member (for example, the return spring S1 in the embodiment) provided in the second valve hole. It is preferable.

  Moreover, the hydraulic coupling device according to the present invention is a hydraulic coupling device configured to include the pressure regulating valve according to the present invention, and includes a first vane pump in which a rotation shaft is coaxially disposed ( For example, the left vane pump PL in the embodiment and the second vane pump (for example, the right vane pump PR in the embodiment), the discharge port communication oil passage that communicates the discharge ports of both vane pumps, and the suction ports of both vane pumps communicate. The first plate member is a side plate of the first vane pump (for example, the right inner side plate 32R in the embodiment), and the second plate member is a side plate of the second vane pump ( For example, from the left inner side plate 32L) in the embodiment. The adjustment pressure supply oil passage formed in the first plate member is connected to the discharge port or the suction port of the first vane pump, and the back pressure supply oil passage formed in the second plate member is the discharge port or the suction port of the second vane pump. It leads to.

  A power transmission device for a four-wheel drive vehicle according to the present invention is a power transmission device for a four-wheel drive vehicle including left and right main drive wheels and left and right auxiliary drive wheels, the hydraulic cup according to the present invention. Each of the first vane pump and the second vane pump is driven by a prime mover (for example, the engine E in the embodiment) together with the left and right main drive wheels, and the rotors of the first vane pump and the second vane pump are It is connected to the axle of the auxiliary drive wheel.

  The pressure regulating valve according to the present invention is configured to open and close the oil passage formed in the first plate member by moving the moving body in the moving body accommodating space. Since it is composed of two members, a first member located on the first valve hole side provided in the one plate member and a second member located on the second valve hole side provided in the second plate member, When the first plate member and the second plate member are joined to each other when the cores are not sufficiently aligned, an axial shift (center axis shift) occurs between the first valve hole and the second valve hole. The influence of the lateral force that the moving body has received from the plate member during the movement in the moving body accommodation space in the related art is the relative movement between the first member and the second member (perpendicular to the axial direction of the moving body accommodation space). Relative movement in the direction) Can move smoothly in the mobile receiving space is Te. Therefore, even if the centering of the plate member is insufficient, the moving body (the first member and the second member) in the moving body accommodation space does not “squeeze”, and the moving body in the moving body accommodation space. There is less risk of problems such as being stuck.

  Moreover, since the hydraulic coupling device according to the present invention includes the pressure regulating valve according to the present invention, when a pressure regulating valve such as a relief valve is necessary between the first and second vane pumps. The assembly becomes easy.

  Moreover, since the power transmission device for a four-wheel drive vehicle according to the present invention includes the hydraulic coupling device according to the present invention that is easy to assemble, it can be configured at low cost.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a skeleton diagram showing a power transmission device for a four-wheel drive vehicle equipped with a hydraulic coupling device to which a pressure regulating valve according to an embodiment of the present invention is applied. As shown in FIG. 1, a four-wheel drive vehicle (hereinafter referred to as a vehicle) V according to the present embodiment includes an engine E disposed horizontally in the front of the vehicle body, and a transmission M coupled to the right side surface of the engine E. Is provided. The first power transmission system D1 that transmits the drive output of the transmission M to the left and right front wheels WFL and WFR as main drive wheels meshes with the first spur gear 2 provided on the output shaft 1 of the transmission M and the first spur gear 2. It comprises a second spur gear 3, a bevel gear type front differential 4 driven by the second spur gear 3, and left and right axles 5L, 5R extending from the front differential 4 to the left and right and connected to the front wheels WFL, WFR. .

  A second power transmission system D2 that transmits the driving force of the first power transmission system D1 to the rear wheels WRL and WRR as auxiliary driving wheels is provided in the differential box of the front differential 4 and rotates integrally with the second spur gear 3. A third spar gear 6, a fourth spar gear 7 meshing with the third spar gear 6, a first bevel gear 8 rotating integrally with the fourth spar gear 7, a second bevel gear 9 meshing with the first bevel gear 8, and a second at the front end. A propeller shaft 10 having a bevel gear 9 extending rearward of the vehicle body, a drive pinion 11 provided at the rear end of the propeller shaft 10, a ring gear 12 meshing with the drive pinion 11, and a hydraulic coupling device H driven by the ring gear 12 And left connected to the rear wheels WRL, WRR extending from the hydraulic coupling device H to the left and right Comprising of axle 13L, and 13R.

  Next, the structure of the hydraulic coupling device H will be described with reference to FIG. The hydraulic coupling device H includes a left vane pump PL and a right vane pump PR arranged symmetrically, a center plate 50 arranged between the two vane pumps PL and PR, and the left and right vane pumps PL and PR and the center plate. And a cylindrical cover member 60 that accommodates 50 therein.

  The left vane pump PL includes a left outer side plate 30L, a left cam ring 31L, a left inner side plate 32L, a left rotor 33L, and a left vane 35L. The right vane pump PR includes a right outer side plate 30R, a right cam ring 31R, a right inner side plate 32R, a right rotor 33R, and a right vane 35R. The left outer side plate 30L, the left cam ring 31L, the left inner side plate 32L, the center plate 50, the right inner side plate 32R, the right cam ring 31R, and the right outer side plate 30R are integrally formed by nine bolts 21 as illustrated. Combined.

  The cover member 60 has a central portion formed in a cylindrical shape, and a right projecting portion 61 that is bent and formed so that an inner peripheral surface thereof is cylindrical is provided at a right end portion. A rightward extending portion 30a having a circular cross section provided to extend rightward from the right end portion of the right outer side plate 30R is fitted inside the rightward protruding portion 61. The right projecting portion 61 of the cover member 60 and the right extending portion 30a of the right outer side plate 30R are coupled to each other by a stopper 22 that is detachably mounted on the outer peripheral surface of the right extending portion 30a. The joint surface between the cover member 60 and the right extension 30a is sealed by an O-ring 23 provided on the outer periphery of the right extension 30a.

  To the left end portion of the cover member 60, a flange portion 30b provided so as to protrude radially outward from the outer peripheral portion of the left outer side plate 30L is joined so as to close the left end opening of the cover member 60. As shown in FIG. 2, the ring gear 12 is attached to the right end surface of the flange portion 30b by a plurality of bolts 24. When the ring gear 12 is attached to the flange portion 30b, the left end portion of the cover member 60 is the left cam ring. It is inserted between the outer peripheral surface of 31L and the ring gear 12. In addition, an O-ring 25 is installed on the inner peripheral surface side of the ring gear 12 during this clamping, and the O-ring 25 is fixedly held between the inner peripheral surface of the ring gear 12 and the outer peripheral surface of the cover member 60. To be.

  The left inner side plate 32L and the right inner side plate 32R are made of sintered metal having a certain thickness, and the center plate 50 is made of a thin steel plate. As can be seen from FIG. 2, the left vane pump PL has a left outer side plate 30L on the left side of the left cam ring 31L and the left rotor 33L, and a left inner side plate 32L on the right side. The PR has a right outer side plate 30R on the right side of the right cam ring 31R and the right rotor 33R, and a right inner side plate 32R on the left side.

  As shown in FIG. 2, a left support portion 30c having an annular cross section is provided so as to protrude leftward from the left side surface of the left outer side plate 30L, and the right outer side plate 30R has a (rightward extension portion). From the right side surface 30a), a right support 30d having an annular cross section is provided so as to protrude rightward. The outer peripheral surface of the left support portion 30 c is supported by the housing 20 via a ball bearing 26, and the outer peripheral surface of the right support portion 30 d is also supported by the housing 20 via a ball bearing 27.

  As shown in FIG. 2, the shaft hole 30e provided in the center of the left outer side plate 30L is provided with a left rotor shaft 90L so as to penetrate the shaft hole 30e, and is provided in the center of the right outer side plate 30R. A right rotor shaft 90R is provided in the shaft hole 30f so as to penetrate the shaft hole 30f. A ball bearing 93 is provided on the inner peripheral surface of the left support portion 30c, and the left rotor shaft 90L is rotatably supported via the ball bearing 93. Further, a ball bearing 94 is provided on the inner peripheral surface of the right support portion 30d, and the right rotor shaft 90R is rotatably supported via the ball bearing 94.

  The left end side of the left rotor shaft 90L protrudes to the left of the left side plate 30L and extends to the left, and the axle 13L of the left rear wheel WRL is provided on the outer peripheral surface of the left rotor shaft 90L. Are coupled via a spline 91L (the axle 13L is not shown in FIG. 2). Further, the right end side of the right rotor shaft 90R protrudes to the right side of the right side plate 30R and extends to the right side so that the axle 13R of the right rear wheel WRR is on the outer peripheral surface of the right rotor shaft 90R. (Axle 13R is not shown in FIG. 2).

  The outer periphery of the left rotor shaft 90L is sealed by an oil seal 95 installed in the left shaft hole 30e, and the outer periphery of the right rotor shaft 90R is sealed by an oil seal 96 installed in the right shaft hole 30f. . Therefore, the two O-rings 23 and 25 and the two oil seals 95 and 96 prevent the hydraulic oil in the left and right vane pumps PL and PR from leaking to the outside, and the left and right vane pumps. Intrusion of air into the PL and PR is prevented.

  A left rotor 33L is attached to a spline 92L provided on the outer peripheral surface of the left rotor shaft 90L by fitting a shaft hole provided in the center thereof, whereby the left rotor 33L is attached to the left outer side plate 30L, It is in a state of being rotatably accommodated in a space surrounded by the left cam ring 31L and the left inner side plate 32L. Further, the right rotor 33R is attached to the spline 92R provided on the outer peripheral surface of the right rotor shaft 90R by fitting the shaft hole provided in the central portion, whereby the right rotor 33R is attached to the right outer side plate. 30R, the right cam ring 31R, and the right inner side plate 32R are in a state of being rotatably accommodated in a space surrounded by the right inner side plate 32R. A roller bearing 97L is provided on the inner peripheral surface of the shaft hole provided in the central portion of the left inner side plate 32L, and a roller bearing is provided on the inner peripheral surface of the shaft hole provided in the central portion of the right inner side plate 32R. 97R is provided, and the roller bearings 97L and 97R respectively rotatably support the right end portion of the left rotor shaft 90L and the left end portion of the right rotor shaft 90R.

  Spaces surrounded by the inner peripheral surfaces of the left and right outer side plates 30L and 30R, the left and right rotors 33L and 33R, the left and right inner side plates 32L and 32R, and the center plate 50 are reservoirs that store hydraulic oil (first reservoir RS1 and This is configured. Further, the space between the cover member 60 and the right outer side plate 30R also constitutes a reservoir (referred to as a second reservoir RS2) that stores hydraulic oil. Further, a space surrounded by the inner peripheral surface of the cover member 60 and the left and right outer side plates 30L and 30R, the left and right cam rings 31L and 31R, the left and right inner side plates 32L and 32R, and the outer peripheral surfaces of the center plate 50 is also a reservoir ( This third reservoir RS3 communicates with the second reservoir RS2, and a plurality of communication grooves g2L, which penetrate the left and right inner side plates 32L, 32R in the radial direction, respectively. It communicates with the first reservoir RS1 via g2R (described later). As described above, the first reservoir RS1, the second reservoir RS2, and the third reservoir RS3 communicate with each other. In the following description, the three reservoirs RS1, RS2, and RS3 may be collectively referred to as a reservoir RS.

  Hereinafter, the structures of the left and right vane pumps PL and PR and the center plate 50 will be described in detail with reference to FIGS. 3 to 13. However, the structure of the left vane pump PL is symmetrical to the structure of the right vane pump PR. In the following, the right structural member will be described, and redundant description of the left structural member will be omitted. The components corresponding to the right vane pump PR and the left vane pump PL are denoted by the same reference numerals with the suffixes “R” and “L”, respectively, and the elements with the same reference numerals are provided at the left and right mirror symmetry positions. Means that

  As shown in FIG. 3, the inner peripheral surface of the right cam ring 31R is formed so as to have three deformed crescent-shaped cam surfaces, and between the circular right rotor 33R housed therein, Three working chambers 34R are formed that are 120 degrees apart in the direction. The right rotor 33R is formed with eight vane grooves 33a extending radially in the outer radial direction, and plate-like right vanes 35R are supported in the vane grooves 33a so as to be slidable in the radial direction. . An annular vane push-up port 33b is formed on both sides of the right rotor 33R, and the bottom of each of the eight vane grooves 33a provided in the right rotor 33R communicates with the vane push-up port 33b. Yes. Further, a coil spring 36 is contracted between the bottom of each vane groove 33a and the radially inner end of the vane 35R so that the radially outer end of each right vane 35R is in close contact with the inner peripheral surface of the right cam ring 31R. ing.

  As shown in FIG. 4, a discharge port 37R facing the one end side of the inner peripheral surface of the working chamber 34R of the right vane pump PR is provided on the right surface of the right inner side plate 32R (the surface facing the right cam ring 31R and the right rotor 33R). And a suction port 38R facing the other end of the inner peripheral surface of the working chamber 34R (see also FIG. 3). Three each of the discharge ports 37R and the suction ports 38R are provided, and the discharge ports 37R and the suction ports 38R are provided at positions that are 120 ° apart from each other in the circumferential direction.

  As shown in FIGS. 4, 5 and 7, each discharge port 37R and each suction port 38R include a communication hole h1R provided through the right inner side plate 32R in the thickness direction, and a right inner side plate 32R. A communication groove g1R that is recessed in the left surface (the surface facing the center plate 50) and a communication hole h2R that is provided through the right inner side plate 32R in the thickness direction and that communicates with the vane push-up port 33b are provided. It has been. Here, as shown in FIG. 7, a stepped valve seat 39a is provided in the communication hole h1R, and a check ball 39b inserted into the communication hole h1R from the left surface side of the right inner side plate 32R. A check valve 39R is constituted by the valve seat 39a. The check valve 39R has a function of allowing the hydraulic oil to flow from the discharge port 37R and the suction port 38R side to the communication hole h2R (that is, the vane push-up port 33b) and blocking the flow of the hydraulic oil in the opposite direction. . The check ball 39b is prevented from dropping from the communication hole h1R by the right center plate 50.

  As shown in FIGS. 4, 5, and 8, each discharge port 37 </ b> R and each suction port 38 </ b> R has a communication hole h <b> 3 </ b> R provided through the right inner side plate 32 </ b> R in the thickness direction, and a right inner side. The reservoir 32 (the first reservoir RS1 and the third reservoir RS3) communicates with the reservoir RS (the first reservoir RS1 and the third reservoir RS3) via the communication groove g2R that is recessed in the left surface of the plate 32R (as described above, the first reservoir RS1 and the third reservoir RS3 are The communication groove g2R communicates with each other). Here, as shown in FIG. 8, a stepped valve seat 40a is provided in the communication hole h3R, and a check ball 40b inserted into the communication hole h3R from the right surface side of the right inner side plate 32R. A check valve 40R is constituted by the valve seat 40a. The check ball 40b is prevented from dropping from the communication hole h3R (by the left cam ring 31L for the check valve 40L on the left inner side plate 32L side) by the right cam ring 31R.

  The check valve 40R has a function of blocking the flow of hydraulic oil from the discharge port 37R and suction port 38R side to the reservoir RS side and allowing the flow of hydraulic oil in the opposite direction. For this reason, when the discharge port 37R becomes high pressure and the suction port 38R becomes low pressure, the high pressure discharged from the high pressure side discharge port 37R while allowing the suction port 38R to suck up hydraulic oil from the reservoir RS. It is possible to prevent the hydraulic oil from flowing into the reservoir RS. On the other hand, when the suction port 38R becomes high pressure and the discharge port 37R becomes low pressure, the discharge port 37R is allowed to suck up the hydraulic oil from the reservoir RS and is discharged from the high pressure side suction port 38R. Oil can be prevented from flowing into the reservoir RS.

  As shown in FIGS. 4, 5, and 9, each discharge port 37R and each suction port 38R also has a communication hole h4R provided through the right inner side plate 32R in the thickness direction, and a right inner side plate 32R. Is communicated with the reservoir RS (with the first reservoir RS1 and the third reservoir RS3) via the communication groove g3R formed in the left side of the first and second communication grooves g2R. Here, as shown in FIG. 9, a stepped valve seat 41a is provided in the communication hole h4R, and a check ball 41b inserted into the communication hole h4R from the right side of the right inner side plate 32R. A check valve 41R is constituted by the valve seat 41a. The check ball 41b is prevented from dropping from the communication hole h4R (the check valve 40L on the left inner side plate 32L side is blocked by the left cam ring 31L) by the right cam ring 31R. The check valve 40R functions in the same manner as the check valve 41R described above.

  As shown in FIGS. 4, 5 and 10, each discharge port 37R is connected to a communication hole h7R provided through the right inner side plate 32R in the thickness direction, and each suction port 38R is connected to the right inner side side. The plate 32R is connected to a communication hole h8R provided through the plate 32R in the thickness direction. The adjacent communication hole h7R and the communication hole h8R are an orifice OF1 (FIG. 6 is also provided) penetrating in the thickness direction through the communication groove g4R formed in the left surface of the right inner side plate 32R and the center plate 50. See), a communication groove g5L recessed in the right surface of the left inner side plate 32L, an orifice OF2 (see also FIG. 6) provided through the center plate 50 in the thickness direction, and a left surface of the right inner side plate 32R. They are communicated with each other through a recessed communication groove g6R. The communication holes h7R connected to the respective discharge ports 37R are communication holes connected to the discharge port 37L on the left side plate 32L side through an orifice OF3 (see also FIG. 6) provided through the center plate 50 in the thickness direction. The communication holes h8R connected to the h7L and connected to the respective suction ports 38R are similarly connected to the suction port on the left side plate 32L via the orifice OF4 (see also FIG. 6) provided through the center plate 50 in the thickness direction. It connects with the communication hole h8L connected to 38L. In this way, the three discharge ports 37R of the right side vane pump PR and the three discharge ports 37L of the left side vane pump PL are mirror-symmetrically arranged (ports) communicate with each other via the orifice OF3. The three suction ports 38R of the PR and the three suction ports 38L of the left vane pump PL are arranged in mirror symmetry (ports) to communicate with each other via the orifice OF4.

  As shown in the upper part of FIG. 4, FIG. 5 and FIG. A configured first relief valve RV1 is provided. The first relief valve RV1 has a movable body composed of two members, a first member B1 and a second member C1, in a movable body accommodating space m1 extending over the three plates 32R, 50, and 32L. By the movement of the moving body in the moving body accommodating space m1, an oil path (a communication hole h9R as an adjustment pressure supply oil path connected to the suction port 38R and a communication groove g2R as a relief oil path connected to the reservoir RS, which will be described later). Road).

  The moving body accommodating space m1 is formed in the right inner side plate 32R by extending in the thickness direction to the right valve hole m2, and the hole m3 formed so as to penetrate the center plate 50 in the thickness direction (also FIG. 6). And a left valve hole m4 formed in the left inner side plate 32L so as to extend in the thickness direction thereof is arranged coaxially (with the central axes substantially aligned). Here, the right valve hole m2 formed in the right inner side plate 32R is connected to the communication hole h9R extending in the thickness direction of the right inner side plate 32R from the suction port 38R, and the connection portion includes the left inner side plate. A tapered valve seat m2a extending to the 32L side (left side in FIG. 11) is formed. The left valve hole m4 formed in the left inner side plate 32L has a large inner diameter portion m4a formed on the right inner side plate 32R side (right side in FIG. 11) and the left cam ring 31L side (in FIG. 11 paper side). A small diameter portion m4b having a small inner diameter formed on the left side is connected coaxially, and a step m4c is formed at the connection portion. Here, the inner diameter of the right valve hole m2 and the inner diameter of the large diameter part m4a of the left valve hole m4 are substantially the same, and the inner diameter of the right valve hole m2 is the inner diameter of the small diameter part m4b of the left valve hole m4 (that is, the left valve hole the inner diameter of the smallest inner diameter portion of m4). Further, the left cam ring 31L side of the small diameter portion m4b is connected to a communication hole h9L extending from the suction port 38L of the left inner side plate 32L (the suction port 38L side of the small diameter portion m4b is a communication hole h9L).

  The first member B1 is formed of a spherical member having an outer diameter that can block the communication between the communication hole h9R and the communication groove g2R when pressed against the valve seat m2a, and is provided on the right valve hole m2 side. The second member C1 is a rod-like member having an outer diameter slightly smaller than the inner diameter of the small diameter portion m4b in the left valve hole m4, and is slidably moved in the small diameter portion m4b of the left valve hole m4. Yes. A return spring S1 is contracted between the stepped portion m4c provided in the left valve hole m4 and the first member B1, and the first member B1 is always urged toward the valve seat m2a. The aforementioned communication groove g2R formed on the left surface of the right inner side plate 32R communicates with the right valve hole m2, and in a state where the first member B1 is pressed against the valve seat m2a as shown in FIG. Communication between the communication hole h9R and the communication groove g2R is blocked, and the communication hole h9R and the communication groove g2R are communicated with each other when the first member B1 is separated from the valve seat m2a as shown in FIG. It has become. As can be seen from FIGS. 12A and 12B, the communication opening degree between the communication hole h9R and the communication groove g2R increases as the distance from the valve seat m2a of the first member B1 increases. Further, the second member C1 has an outer diameter slightly smaller than the inner diameter of the small diameter portion m4b of the left valve hole m4 and is movable within the small diameter portion m4b, and is in the communication hole h9L as a back pressure supply oil passage. In response to this pressure, the first member B1 is constantly urged toward the valve seat side and the communication between the communication hole h9L and the left valve hole m4 is always blocked.

  Further, as shown in the lower part of FIGS. 4, 5, and 11, these three plates 32L, 50, and 32R are provided at positions near the joining surfaces of the left inner side plate 32L, the center plate 50, and the right inner side plate 32R. A second relief valve RV2 that is configured to be included is provided. The second relief valve RV2 has a moving body composed of two members, a first member B2 and a second member C2, in a moving body accommodating space n1 extending over the three plates 32L, 50, and 32R. By the movement of the moving body in the moving body accommodating space n1, an oil path (a communication hole h10L serving as an adjustment pressure supply oil path connected to the suction port 38L and a communication groove g2L serving as a relief oil path connected to the reservoir RS is described. Road).

  The movable body accommodating space n1 is formed in the left inner side plate 32L by extending in the thickness direction on the left valve hole n2, and the hole n3 formed so as to penetrate the center plate 50 in the thickness direction (also in FIG. 6). And right valve hole n4 formed in the right inner side plate 32R so as to extend in the thickness direction thereof are arranged coaxially (with the central axes substantially aligned). Here, the left valve hole n2 formed in the left inner side plate 32L is connected to the communication hole h10L extending in the thickness direction of the left inner side plate 32L from the suction port 38L, and the right inner side plate is connected to the connecting portion. A tapered valve seat n2a extending to the 32R side (the right side in FIG. 11) is formed. The right valve hole n4 formed in the right inner side plate 32R has a large inner diameter portion n4a formed on the left inner side plate 32L side (left side in FIG. 11) and the right cam ring 31L side (paper surface in FIG. 11). The small-diameter portion n4b having a small inner diameter formed on the right side) is coaxially connected, and a step n4c is formed at the connecting portion. Here, the inner diameter of the left valve hole n2 and the inner diameter of the large diameter part n4a of the right valve hole n4 are substantially the same, and the inner diameter of the left valve hole n2 is the inner diameter of the small diameter part n4b of the right valve hole n4 (that is, the right valve hole (the inner diameter of the smallest inner diameter portion of n4). The right cam ring 31L side of the small diameter portion n4b is connected to a communication hole h10R extending from the suction port 38R of the right inner side plate 32R (the suction port 38R side of the small diameter portion n4b is a communication hole h10R).

  The first member B2 is formed of a spherical member having an outer diameter that can block communication between the communication hole h10L and the communication groove g2L when pressed against the valve seat n2a, and is provided on the left valve hole n2 side. The second member C2 is a rod-like member having an outer diameter slightly smaller than the inner diameter of the small diameter portion n4b in the right valve hole n4, and is slidably moved in the small diameter portion n4b of the right valve hole n4. Yes. A return spring S2 is contracted between the step n4c provided in the right valve hole n4 and the first member B2, and the first member B2 is always urged toward the valve seat n2a. The communication groove g2L formed on the right surface of the left inner side plate 32L communicates with the left valve hole n2. When the first member B2 is pressed against the valve seat n2a, the communication hole h10L and the communication groove g2L are in communication with each other. The communication hole h10L and the communication groove g2L are communicated with each other in a state where the first member B2 is blocked and separated from the valve seat n2a. As in the case of the first relief valve RV1, the communication opening degree between the communication hole h10L and the communication groove g2L increases as the distance from the valve seat n2a of the first member B2 increases. The second member C2 has an outer diameter slightly smaller than the inner diameter of the small-diameter portion n4b of the right valve hole n4 and is movable within the small-diameter portion n4b, and is in the communication hole h10R as a back pressure supply oil passage. In response to this pressure, the first member B2 is constantly urged toward the valve seat and the communication between the communication hole h10R and the right valve hole n4 is always blocked.

  FIG. 13 is a hydraulic circuit diagram showing the configuration of the hydraulic coupling device H. In this hydraulic circuit diagram, for the sake of simplicity and clarity, the three discharge ports 37R in the right vane pump PR are shown together as one, and the three suction ports 38R are shown as one. Similarly, the three discharge ports 37L in the left vane pump PL are collectively shown as one, and the three suction ports 38L are collectively shown as one.

  As shown in this hydraulic circuit diagram, in the hydraulic coupling device H, the discharge port 37R of the right vane pump PR is connected to an oil passage that leads to the suction port 38R via two orifices OF1R and OF2R, and a reservoir via the check valve 40R. An oil passage that leads to the RS and an oil passage that leads to the reservoir RS via the check valve 41R. The suction port 38R of the right vane pump PR has an oil passage that leads to the discharge port 37R via the two orifices OF2R and OF1R; It has an oil passage that leads to the reservoir RS via the check valve 40R, an oil passage that leads to the reservoir RS via the check valve 41R, and an oil passage that leads to the reservoir RS via the first relief valve RV1. For this reason, in the right vane pump PR, when the discharge port 37R becomes the high pressure side and the suction port 38R becomes the low pressure side with the operation of the vehicle V, the check valve 40R and the check valve 41R on the discharge port 37R side become the discharge port 37R. The high pressure hydraulic oil discharged from the discharge port 37R cannot flow into the reservoir RS via the communication hole h3R or the communication hole h4R, and the path passes through the orifices OF1R and OF2R. Thus, the air flows into the suction port 38R. On the other hand, the check valve 40R and the check valve 41R on the suction port 38R side are opened by the suction pressure (negative pressure) of the suction port 38R, so that the hydraulic oil in the reservoir RS is sucked through the communication hole h3R and the communication hole h4R. It flows into the port 38R.

  On the contrary, when the suction port 38R becomes a high pressure side and the discharge port 37R becomes a low pressure side as the vehicle V is operated, the check valve 40R and the check valve 41R on the suction port 38R side are connected to the suction port 38R. The high pressure hydraulic oil discharged from the suction port 38R cannot flow into the reservoir RS via the communication hole h3R or the communication hole h4R, and passes through the orifices OF2R and OF1R. (In some cases, a part of the hydraulic oil discharged from the suction port 38R is returned from the first valve RV1 to the reservoir RS. This case will be described later). On the other hand, since the check valve 40R and the check valve 41R on the discharge port 37R side are opened by the suction pressure of the discharge port 37R, the hydraulic oil in the reservoir RS passes through the communication hole h3R and the communication hole h4R and enters the discharge port 37R. Inflow.

  Further, the discharge port 37L of the left vane pump PL has an oil passage that leads to the suction port 38L via two orifices OF1L and OF2L, an oil passage that leads to the reservoir RS via the check valve 40L, and an oil passage that leads to the reservoir RS via the check valve 41L. The intake port 38L of the left vane pump PL is connected to the discharge port 37L via the two orifices OF2L and OF1L, the oil path connected to the reservoir RS via the check valve 40L, and the check valve 41L. And an oil passage that communicates with the reservoir RS and a fluid passage that communicates with the reservoir RS via the second relief valve RV2. For this reason, in the left vane pump PL, when the discharge port 37L becomes a high pressure side and the suction port 38L becomes a low pressure side as the vehicle V is operated, the check valve 40L and the check valve 41L on the discharge port 37L side become the discharge port 37L. The high pressure hydraulic oil discharged from the discharge port 37L cannot flow into the reservoir RS via the communication hole h3L or the communication hole h4L, and passes through the orifices OF1L and OF2L. Thus, it flows into the suction port 38L. On the other hand, since the check valve 40L and the check valve 41R on the suction port 38L side are opened by the suction pressure of the suction port 38L, the hydraulic oil in the reservoir RS passes through the communication hole h3L and the communication hole h4L and enters the suction port 38L. Inflow.

  On the other hand, when the suction port 38L becomes the high pressure side and the discharge port 37L becomes the low pressure side with the operation of the vehicle V, the check valve 40L and the check valve 41L on the suction port 38L side become the suction port 38L. The high pressure hydraulic oil discharged from the suction port 38L cannot flow into the reservoir RS via the communication hole h3L or the communication hole h4L, and passes through the orifices OF2L and OF1L. In this case, a part of the hydraulic oil discharged from the suction port 38L may be returned from the second valve RV2 to the reservoir RS. This case will be described later. On the other hand, since the check valve 40L and the check valve 41L on the discharge port 37L side are opened by the suction pressure of the discharge port 37L, the hydraulic oil in the reservoir RS passes through the communication hole h3L and the communication hole h4L and enters the discharge port 37L. Inflow.

  Further, since the discharge port 37R and the suction port 38R of the right vane pump PR communicate with the vane push-up port 33b of the right rotor 33R via the check valve 39R, respectively, the discharge port 37R and the suction port 38R have a high pressure. This pressure acts on the vane push-up port 33b. As a result, each right vane 35R is urged outward in the radial direction, and its tip is pressed against the inner peripheral surface of the right cam ring 31R. On the other hand, the check valve 39R connected to the lower pressure port is closed by the pressure acting from the vane push-up port 33b side. Similarly, since the discharge port 37L and the suction port 38L of the left vane pump PL communicate with the vane push-up port 33b of the left rotor 33L via the check valve 39L, respectively, the discharge port 37L and the suction port 38L have a high pressure. The pressure which becomes becomes acts on the vane push-up port 33b. As a result, each left vane 35L is urged radially outward, and its tip is pressed against the inner peripheral surface of the left cam ring 31L. Further, the check valve 39L connected to the lower pressure port is closed by the pressure acting from the vane push-up port 33b side.

  In the hydraulic coupling device H, the discharge port 37R of the right side vane pump PR and the discharge port 37L of the left side vane pump PL communicate with each other through a discharge port communication oil path including both communication holes h7R and h7L and an orifice OF3. The suction port 38R of the right side vane pump PR and the suction port 38L of the left side vane pump PL communicate with each other through a suction port communication oil path including both communication holes h8R and h8L and an orifice OF4. For this reason, when there is a difference between the discharge flow rates of the left and right vane pumps PL and PR, the hydraulic oil flows through the discharge port communication oil passage or the suction port communication oil passage from the high discharge flow rate side to the low discharge flow rate side. However, since the orifice OF3 is provided between the communication holes h7R and h7L of the discharge port communication oil passage, at least one of the discharge ports 37R and 37L serves as a discharge side, and both the discharge ports 37R and 37L. When there is a difference in the flow rate of the hydraulic oil discharged from the flow, a flow resistance corresponding to the flow rate works, and a pressure difference is generated before and after the orifice OF3. Similarly, since the orifice OF4 is provided between the communication holes h8R, h8L of the suction port communication oil passage, at least one of the suction ports 38R, 38L serves as a discharge side and both the suction ports 38R. , 38L, there is a difference in the flow rate of the hydraulic oil discharged, a flow resistance corresponding to the flow rate acts, and a pressure difference is generated before and after the orifice OF4.

  Further, the hydraulic coupling device H has the first relief valve RV1 as described above, and the first relief valve RV1 is guided through the communication hole h9R as the adjustment pressure supply oil passage. The pressure in the suction port 38R causes a force F1R to urge the first member B1 in the valve opening direction against the urging force of the return spring S1, and the return spring S1 causes the first member B1 to close in the valve closing direction by the spring force. The force F2R for biasing and the force for biasing the first member B1 in the valve closing direction via the second member C1 by the pressure in the suction port 38L led through the communication hole h9L as the back pressure supply oil passage When the relationship with F3R becomes F1R> F2R + F3R, the valve is opened at an opening corresponding to the difference in force (F1R− (F2R + F3R)), and the communication hole h9R and the communication groove g2R are communicated. As a result, when the suction port 38R of the right vane pump PR becomes a discharge side port, when the pressure in the suction port 38R becomes larger than the pressure in the suction port 38L of the left vane pump PL by a certain amount or more, Part of the hydraulic oil discharged from the port 38R is returned (that is, relieved) to the reservoir RS.

  Further, the hydraulic coupling device H has a second relief valve RV2, and the second relief valve RV2 is a pressure in the suction port 38L guided through a communication hole h10L as an adjustment pressure supply oil passage. Is a force F1L that urges the first member B2 in the valve opening direction against the urging force of the return spring S2, and a force F2L that the return spring S2 urges the first member B2 in the valve closing direction by the spring force. The relationship between the pressure in the suction port 38R guided through the communication hole h10R serving as the back pressure supply oil passage and the force F3L that biases the first member B2 in the valve closing direction through the second member C2 is F1L. When> F2L + F3L, the valve is opened at an opening corresponding to the difference in force (F1L− (F2L + F3L)), and the communication hole h10L and the communication groove g2L are communicated. As a result, when the suction port 38L of the left vane pump PL becomes a discharge side port, when the pressure in the suction port 38L becomes larger than the pressure in the suction port 38R of the right vane pump PR by a certain amount or more, Part of the hydraulic oil discharged from the port 38L is returned (relieved) to the reservoir RS.

  In the first relief valve RV1, as shown in FIG. 11, the area (pressure receiving area) where the pressure in the communication hole h9L as the back pressure supply oil path acts on the second member C1, and the adjusted pressure supply oil path The pressure in the communication hole h9R is approximately the same as the area acting on the closed first member B1, but the first member B1 is always closed by the return spring S1. Therefore, if the pressure of the hydraulic oil in the communication hole h9R is not extremely high compared to the pressure of the hydraulic oil in the communication hole h9L, the first member B1 is in the valve opening direction. Do not move. However, the conditions for opening the first member B1 can be arbitrarily set by setting the both pressure receiving areas and the value of the spring constant of the return spring S1 (second relief valve RV2). The same applies to.

  Next, the specific operation | movement according to the driving | running | working state of the vehicle V of the hydraulic coupling apparatus H which is a power transmission device of the four-wheel drive vehicle provided with the above-mentioned structure is demonstrated. When the vehicle V is traveling forward or backward, the driving force of the engine E is transmitted from the output shaft 1 of the transmission M to the left and right through the first spur gear 2, the second spur gear 3, the front differential 4, and the left and right axles 5L and 5R. Are transmitted to the front wheels WFL, WFR. At this time, the rotation of the third spur gear 6 of the front differential 4 is caused by rotation of the hydraulic coupling device H via the fourth spur gear 7, the first bevel gear 8, the second bevel gear 9, the propeller shaft 10, the drive pinion 11 and the ring gear 12. The left and right cam rings 31L and 31R are rotated. On the other hand, the rotation of the rear wheels WRL, WRR driven by the frictional force received from the road surface as the vehicle V travels causes the rotors of the left and right vane pumps PL, PR from the left and right axles 13L, 13R through the rotor shafts 90L, 90R. 33L and 33R are transmitted. In this vehicle V, when the rotational speeds of the front wheels WFL and WFR are equal to the rotational speeds of the rear wheels WRL and WRR, the rotational speeds of the left and right cam rings 31L and 31R and the rotational speeds of the left and right rotors 33L and 33R are made to coincide. Configured.

  Here, when the vehicle V is traveling at a constant speed or normal acceleration / deceleration, and the rotational speed of the front wheels WFL and WFR is equal to the rotational speed of the rear wheels WRL and WRR, the left cam ring 31L and the left rotor 33L No relative rotation occurs between the right cam ring 31R and the right rotor 33R. As a result, the left and right vane pumps PL and PR do not perform the pump operation, and the hydraulic coupling device H does not transmit the driving force, so that the vehicle V enters a two-wheel drive state in which only the front wheels are driven.

  When the vehicle V suddenly starts on a low friction road and the front wheels WFL and WFR to which the driving force of the engine E acts directly slip, the rotational speed of the front wheels WFL and WFR is the rotational speed of the rear wheels WRL and WRR. Bigger than. In this case, left and right vane pumps PL and PR pump cam rings 31R and 31L that rotate in conjunction with the rotation of front wheels WFL and WFR, and left and right vane pumps PL that rotate in conjunction with the rotation of rear wheels WRL and WRR. , And the PR rotors 33L and 33R generate relative rotation (the relative rotation direction at this time is defined as the normal rotation direction). For example, in the case of the right vane pump PR, the relative rotation in the normal rotation direction is a rotation in a direction in which the right rotor 33R rotates counterclockwise (arrow A direction) with the right cam ring 31R fixed in FIG.

  Thus, when the rotational speed of the front wheels WFL, WFR exceeds the rotational speed of the rear wheels WRL, WRR, and the rotors 33L, 33R rotate relative to the cam rings 31L, 31R in the forward rotation direction, the suction ports 38L, 38R From the discharge ports 37L and 37R. At this time, the hydraulic oil discharged from the discharge ports 37L and 37R on the high pressure side opens the check valves 39L and 39R and flows into the vane push-up ports 33b and 33b, and the tips of the vanes 35L and 35R are connected to the cam ring 31L. , 31R is pressed against the inner peripheral surface.

  The vanes 35L and 35R pressed against the inner peripheral surfaces of the cam rings 31L and 31R by the high-pressure hydraulic oil flowing into the vane push-up ports 33b and 33b have their radially outer ends at the inner peripheral surfaces of the cam rings 31L and 31R. Rotates with the rotors 33L and 33R while being in sliding contact with each other. Here, as described above, on the inner peripheral surfaces of the cam rings 31L and 31R, three working chambers separated by 120 ° in the inner circumferential direction (the three working chambers 34R described above in the right vane pump PR) are formed. In addition, since each of the working chambers is formed in a deformed crescent shape, when the vanes 35L and 35R rotate in the forward rotation direction together with the rotors 33L and 33R, the adjacent vanes in the working chamber and the inner periphery of the cam rings 31L and 31R. The volume of the space surrounded by the surfaces and the outer peripheral surfaces of the rotors 33L and 33R (referred to as pump space) varies. As a result, the vanes 35L and 35R in the working chamber have a high pressure region in the traveling direction and a low pressure region in the traveling direction.

  As a result, the hydraulic oil in the reservoir RS is sucked up to the suction ports 38L and 38R via the check valves 40L and 40R and the check valves 41L and 41R on the suction ports 38L and 38R, and then operated at a higher pressure than the discharge ports 37L and 37R. It is discharged as oil. The high-pressure hydraulic oil discharged from the discharge ports 37L and 37R passes through the orifices OF1L and OF2L or the orifices OF1R and OF2R, and after being reduced in pressure, is returned to the suction ports 38L and 38R. Between the discharge port 37L and the suction port 38L, the right vane pump PR recirculates between the discharge port 37R and the suction port 38R.

  As described above, the high-pressure hydraulic oil discharged from the discharge ports 37L and 37R flows through the orifices (orifices OF1L and OF2L or orifices OF1R and OF2R), respectively. Due to the flow resistance, a load is generated in the left and right vane pumps PL and PR. Due to this load, the rotors 33L, 33R receive driving force from the cam rings 31L, 31R, and this driving force is transmitted to the left and right rear wheels WRL, WRR. Therefore, in the present vehicle V, when the front wheels WFL and WFR slip as described above, the vehicle V enters a four-wheel drive state in which not only the front wheels but also the rear wheels are driven, and the traction of the vehicle V increases. As the diameter of the orifices (orifices OF1L, OF2L, OF1R, OF2R) is smaller, the loads on the left and right vane pumps PL, PR increase, and the driving force of the rear wheels WRL, WRR increases.

  When the vehicle V turns, the average turning radius of the left and right rear wheels WRL, WRR is smaller than the average turning radius of the front wheels WFL, WFR, and the inner wheel side of the rear wheels WRF, WRR is smaller than the outer wheel side. Since the average turning radius becomes small, relative rotation occurs between the left cam ring 31L and the left rotor 33L and between the right cam ring 31R and the right rotor 33R. Further, the relative rotational speed between the left cam ring 31L and the left rotor 33L is different from the relative rotational speed between the right cam ring 31R and the right rotor 33R. Even in such a case, the hydraulic oil discharged from the discharge port 37L of the left vane pump PL returns to the suction port 38L of the left vane pump PL through the orifices OF1L and OF2L, and is discharged from the discharge port 37R of the right vane pump PR. Is returned to the suction port 38R of the right vane pump PR through the orifices OF1R and OF2R. However, the flow rate of the discharged hydraulic oil is different between the left and right vane pumps PL and PR. The hydraulic fluid flows through an oil passage (the above-described discharge port communication oil passage) connecting the discharge ports 37L and 37R.

  For example, when the vehicle turns in the left direction, the left rear wheel WRL becomes an inner wheel and the right rear wheel WRR becomes an outer wheel. At this time, the relative relationship between the left cam ring 31L and the left rotor 33L in the left vane pump PL. The rotational speed is higher than the relative rotational speed between the right cam ring 31R and the right rotor 33R in the right vane pump PR. For this reason, the flow rate of the hydraulic oil discharged from the left vane pump PL is larger than the flow rate of the hydraulic oil discharged from the right vane pump PR, and the difference between them is an oil passage connecting the discharge ports 37L and 37R (discharge port connection). Therefore, the difference in rotational speed between the left and right auxiliary drive wheels WRL and WRR is absorbed, and the function as a differential mechanism is exhibited. This also prevents a large load from acting on the vane pump on the side where the discharge flow rate is increased even during tight turning, and the occurrence of the so-called tight corner braking phenomenon is also suppressed. The orifice OF3 is interposed in the oil passage connecting the discharge ports 37L and 37R, but the flow rate of the hydraulic oil flowing between the left and right vane pumps PL and PR during the turning travel is small, and the pressure difference generated before and after the orifice OF3. Is extremely small, so that the function as the differential mechanism is not hindered.

  Next, consider a case where one of the rear wheels WRL, WRR, for example, the left and right front wheels WFL, WFR and the right rear wheel WRR except for the left rear wheel WRL are trapped. In this case, the left and right front wheels WFL, WFR trapped in mud slip and rotate at high speed (idle), and the left and right cam rings 31L, 31R also rotate at high speed, but the right rear wheel WRR Like the front wheels WFL and WFR, the road surface resistance is reduced due to mud, so even if the power from the engine E is transmitted, it rotates (idls) at the same high speed as the front wheels WFL and WFR. For this reason, the rotational speed of the right cam ring 31R and the rotational speed of the right rotor 33R are very close, and the relative rotational speed difference is reduced, while the left rotor 33L connected to the non-slip left rear wheel WFL and the left rotor 33L The relative rotational speed between the cam ring 31L and the cam ring 31L becomes very large, and the flow rate of the hydraulic oil discharged from the left vane pump PL is larger than the flow rate of the hydraulic oil discharged from the right vane pump PR.

  As described above, when the discharge flow rate from the left vane pump PL becomes larger than the discharge flow rate from the right vane pump PR, the hydraulic oil discharged from the left vane pump PR tends to flow to the right vane pump PR side. Here, if the orifice OF3 is not interposed in the oil passage (discharge port communication oil passage) connecting the discharge ports 37L and 37R of the vane pumps PL and PR, the hydraulic oil discharged from the left vane pump PL is The discharge port 37L is not maintained at a high pressure because it can move to the right vane pump PR without flow resistance, and the hydraulic oil discharged from the discharge port 37L does not pass through the orifices OF1L and OF2L. Therefore, not only the right rear wheel WRR but also the left rear wheel This is where the driving force is not transmitted to the WRL. However, as described above, since the orifice OF3 is interposed in the oil passage (discharge port communication oil passage) connecting the discharge ports 37L and 37R of the two vane pumps PL and PR, the left and right vane pumps as in this case. When the difference in the discharge flow rate of the hydraulic oil from PL and PR is extremely large, the flow resistance of the hydraulic oil discharged from the left vane pump PL to the right vane pump PR side is restricted by the flow path resistance of the orifice OF3. Thus, a pressure difference is generated before and after the orifice OF3, and the discharge port 37L of the left vane pump PL is maintained at a high pressure. As a result, the hydraulic oil discharged from the discharge port 37L of the left vane pump PL passes through the orifices OF1L and OF2L and a load is generated, so that the driving force is transmitted from the left cam ring 31L to the left rotor 33L. Thus, the vehicle V can escape from the mud. Thus, the hydraulic coupling device H shown in the present embodiment has the same function as a so-called operation restriction device (LSD). The smaller the diameter of the two orifices OF3, the more the function is achieved. Can strengthen.

  When sudden braking is performed during forward travel and the front wheels WFL and WFR appear to be locked (at this time, the front wheels WFL and WFR slip), the rotational speed of the rear wheels WRL and WRR is the same as the rotational speed of the front wheels WFL and WFR. It exceeds. As a result, a relative rotation in the reverse direction occurs between the cam rings 31R, 31L of the left and right vane pumps PL, PR and the rotors 33L, 33R. For example, in the case of the right vane pump PR, the relative rotation in the reverse direction is a rotation in a direction in which the right rotor 33R rotates clockwise (in the direction of arrow B) with the right cam ring 31R fixed in FIG.

  Thus, when the rotational speed of the rear wheels WRL, WRR exceeds the rotational speed of the front wheels WFL, WFR, and the rotors 33L, 33R rotate relative to the cam rings 31L, 31R in the reverse direction, the discharge ports 37L, 37R The hydraulic oil is sucked and discharged from the suction ports 38L and 38R. At this time, the hydraulic oil discharged from the suction ports 38L and 38R on the high pressure side opens the check valves 39L and 39R and flows into the vane push-up ports 33b and 33b, and the tips of the vanes 35L and 35R are connected to the cam ring 31L. , 31R is pressed against the inner peripheral surface.

  The vanes 35L and 35R pressed against the inner peripheral surfaces of the cam rings 31L and 31R by the high-pressure hydraulic oil flowing into the vane push-up ports 33b and 33b have radially outer ends at the inner peripheral surfaces of the cam rings 31L and 31R. Rotates with the rotors 33L and 33R while being in sliding contact with each other. As a result, the vanes 35L and 35R in the working chamber have a high pressure region in the traveling direction and a low pressure region in the traveling direction.

  As a result, the hydraulic oil in the reservoir RS is sucked up to the discharge ports 37L and 37R via the check valves 40L and 40R and the check valves 41L and 41R on the discharge ports 37L and 37R, and then operated at a higher pressure than the suction ports 38L and 38R. It is discharged as oil. The high-pressure hydraulic oil discharged from the suction ports 38L and 38R passes through the orifices OF2L and OF1L or the orifices OF2R and OF1R, and after being reduced in pressure, is returned to the discharge ports 37L and 37R. In the right vane pump PR, the air flows back between the suction port 38L and the discharge port 37L, and between the suction port 38R and the discharge port 37R.

  In this way, the high-pressure hydraulic oil discharged from the suction ports 38L and 38R flows through the orifices (orifices OF2L and OF1L or orifices OF2R and OF1R), respectively. Accordingly, a load is generated in the left and right vane pumps PL, PR, and a force in a direction that prevents the vehicle V from moving forward, that is, a braking force, is transmitted to the left and right rear wheels WRL, WRR.

  Here, when one of the left and right rear wheels WRL, for example, the left rear wheel WRL slips on a road surface having a low friction coefficient, the left side of the left vane pump PL connected to the slipping left rear wheel WRL. The rotational speed of the rotor 33L becomes close to the rotational speed of the left cam ring 31L, and the pump operation is not performed (the driving force from the engine E is not transmitted), while the vane pump PR connected to the non-slip right rear wheel WRR. Since the pump operation is continued, there is a large difference in the flow rate of hydraulic oil discharged from the left and right vane pumps PL and PR. The hydraulic oil discharged from the right vane pump PR having a large discharge flow rate is subjected to a flow resistance at the orifice OF4 and increases its pressure, resulting in a large difference in the discharge pressures of the left and right vane pumps PL and PR (right side). The pressure in the suction port 38R of the vane pump PR becomes higher than the pressure in the suction port 38L of the left vane pump PL).

  At this time, the first member B1 of the first relief valve RV1 receives the force in the valve opening direction due to the pressure in the suction port 38R of the right vane pump PR transmitted through the communication hole h9R as the adjustment pressure supply oil passage. Thus, the force in the valve closing direction due to the pressure in the suction port 38L of the left vane pump PL transmitted through the communication hole h9L as the back pressure supply oil passage (this force is applied to the first member B1 via the second member C1. In the state where the pressure in the suction port 38R of the right vane pump PR is extremely higher than the pressure in the suction port 38L of the left vane pump PL, the cause of the biasing force in the valve closing direction by the return spring S1 is received. Even if the urging force is taken into consideration, the urging force in the direction in which the first member B1 is opened is superior to the urging force against this, so the first member B1 moves in the valve opening direction. Accordingly, the communication hole h9R as the adjustment pressure supply oil passage and the communication groove g2R as the relief oil passage communicate with each other, and the hydraulic oil discharged from the suction port 38R of the right side vane pump PR on the high pressure side is communicated with the communication hole h9R. Relieved to the reservoir RS via the groove g2R (see FIG. 12B), the discharge pressure of the right vane pump PR, which has a high discharge pressure, is lowered, and as a result, the right rear wheel WRR on the non-slip side is transmitted. The driving force from the engine E is reduced. This is a function to weaken the above-mentioned differential limitation, and the driving force difference between the left and right auxiliary driving wheels is reduced, so one of the left and right rear wheels slips when sudden braking is performed during forward traveling. Even in such a case, a situation where a torque difference occurs between the left and right rear wheels WRL, WRR and the vehicle traveling becomes unstable is prevented.

  The same applies to the case where the right rear wheel WRR slips when sudden braking is being performed during forward travel. At this time, the pressure in the suction port 38L of the left vane pump PL on the high pressure side and the right side on the low pressure side are the same. The second relief valve RV2 is operated by the difference with the pressure in the suction port 38R of the vane pump PR, and the communication hole h10L as the adjustment pressure supply oil passage and the communication groove g2L as the relief oil passage are communicated. As a result, the hydraulic oil discharged from the suction port 38L of the left side vane pump PL on the high pressure side is relieved through the communication hole h10L and the communication groove g2L, and is connected to the left rear wheel WRL on the non-slip side. Since the pump operation is not performed, the driving force from the engine E is not transmitted to the left rear wheel WRL, and the above effect can be obtained.

  That is, in the hydraulic coupling device H, the first and second relief valves RV1 and RV2 allow the rotational speeds of the left and right rear wheels WRF and WRR, which are auxiliary driving wheels, to be the left and right front wheels WFL, which are the main driving wheels, When the rotational speed of the WFR is exceeded, the hydraulic fluid on the high-pressure side of either of the suction ports 38L and 38R is relieved, so that it is easy to escape from the state where it is trapped in mud. In the case of sudden braking while traveling forward while utilizing the differential limiting function, if one of the left and right auxiliary drive wheels slips, it is transmitted from the power source to the non-slip auxiliary drive wheel. The driving force can be reduced, and a torque difference can be prevented from occurring between the left and right auxiliary driving wheels, thereby ensuring sufficient running stability.

  The pressure when the first relief valve RV1 and the second relief valve RV2 are opened (that is, the relief pressure) is applied to the return springs S1 and S2 that urge the first members B1 and B2 in the valve closing direction. Since it can be adjusted as desired by changing the power, it is possible to provide an optimum relief characteristic for each vehicle to which the hydraulic coupling device H is applied.

  Further, in the first relief valve RV1 provided in the hydraulic coupling device H, an oil passage (supplied oil) formed in the right inner side plate 32R when the moving body moves in the moving body accommodating space m1. The communication passage h9R as a passage and an oil passage composed of a communication groove g2R as a relief oil passage) are opened and closed. The moving body is provided in the right inner side plate 32R in the moving body accommodation space m1. The first member B1 located on the right valve hole m2 side and the second member C1 located on the left valve hole m4 side provided in the left inner side plate 32L of the moving body accommodating space m1 are configured. Therefore, when the right inner side plate 32R, the center plate 50, and the left inner side plate 32L are joined, the centering is insufficient, and the right side plate When the axial displacement (displacement of the central axis) occurs between the lube hole m2 and the left valve hole m4 (and with the center plate 50), the conventional movable body moves when moving in the movable body accommodating space m1. Since the influence of the lateral force received from these plates 32R, 50, and 32L is absorbed by the relative movement between the first member B1 and the second member C1, the entire movable body is within the movable body accommodating space m1. Can move smoothly. Therefore, even if the alignment of the side plates 32R and 32L (and also the center plate 50) is insufficient, the moving body accommodating space formed in the side plates 32R and 32L (and further in the center plate 50). The “moving body” in the m1 (the first member B1 and the second member C1) does not “squeeze”, and the possibility that the moving body does not move in the moving body accommodation space m1 is reduced (second relief). The same applies to the valve RV2.)

  Although the preferred embodiments of the present invention have been described so far, the scope of the present invention is not limited to those shown in the above-described embodiments. For example, in the first relief valve RV1, the inner diameter of the minimum inner diameter portion (corresponding to the small diameter portion m4b of the left valve hole m4) in the left valve hole m4 constituting the moving body accommodating space m1 is smaller than the inner diameter of the right valve hole m2. In addition, the second member C1 has a configuration including a requirement of a rod-shaped member having an outer diameter slightly smaller than the inner diameter of the minimum inner diameter portion in the left valve hole m4. However, this is an example, The one relief valve RV1 does not necessarily have such a requirement. However, if the first relief valve RV1 has the above-mentioned requirements, the right valve hole m2 and the left valve are larger than the case where the inner diameter of the right valve hole m2 and the inner diameter of the minimum inner diameter portion of the left valve hole m4 are the same. It is possible to increase the allowable amount of the axial deviation that occurs between the hole m4 (the same applies to the second relief valve RV2).

  In the first relief valve RV1 according to the above embodiment, the communication hole h9R as the adjustment pressure supply oil passage extends coaxially with the central axis of the right valve hole m2, and the communication groove g2R as the relief oil passage has the right valve. It extends in a direction substantially perpendicular to the central axis of the hole m2, and has a configuration in which a tapered valve seat m2a extending to the left inner side plate 32L side is formed at the connecting portion between the communication hole h9R and the right valve hole m2. However, this is an example, and the first relief valve RV1 does not necessarily have such a configuration. However, if the first relief valve RV1 is configured as described above, the oil passage (the communication hole h9R and the communication groove g2R) can be reliably shut off with a simple configuration (about the second relief valve RV2). The same).

  The pressure regulating valve according to the present invention (corresponding to the first and second relief valves RV1 and RV2 described above) is not limited to the hydraulic coupling device, but can be applied to other hydraulic devices. In a hydraulic coupling device assembled by joining plate members, when it is necessary to provide a pressure regulating valve such as a relief valve between the left and right vane pumps, the assembly is performed by applying the pressure regulating valve according to the present invention. There is an advantage that becomes very easy. When the pressure regulating valve according to the present invention is applied to the hydraulic coupling device, as in the above example, the suction ports 38L and 38R of the left and right vane pumps PL and PR are targeted for the adjustment pressure. In addition, the discharge ports 37L and 37R of the left and right vane pumps PL and PR can be adjusted. In addition, the hydraulic coupling device to which the pressure regulating valve according to the present invention is applied is not limited to the case where it is used in a power transmission device of a four-wheel drive vehicle as in the above-described example, and other power devices may be used. Although applicable, if the power transmission device of a four-wheel drive vehicle includes the hydraulic coupling device according to the present invention that is easy to assemble, it can be configured at low cost. It becomes.

It is a skeleton figure which shows the structure of the power transmission device of the four-wheel drive vehicle provided with the hydraulic coupling device to which the pressure regulation valve which concerns on one Embodiment of this invention was applied. It is sectional drawing of the hydraulic coupling apparatus with which the power transmission device of the said four-wheel drive vehicle was equipped. It is sectional drawing of the hydraulic coupling apparatus seen from the arrow III-III in FIG. It is sectional drawing of the hydraulic coupling device seen from arrow IV-IV in FIG. It is sectional drawing of the hydraulic coupling apparatus seen from the arrow VV in FIG. It is sectional drawing of the hydraulic coupling apparatus seen from the arrow VI-VI in FIG. It is sectional drawing about a part of right inner side plate, center plate, left inner side plate, and cover member in a hydraulic coupling device. It is sectional drawing about a part of right inner side plate, center plate, left inner side plate, and cover member in a hydraulic coupling device. It is sectional drawing about a part of right inner side plate, center plate, left inner side plate, and cover member in a hydraulic coupling device. It is sectional drawing about a part of right inner side plate, center plate, left inner side plate, and cover member in a hydraulic coupling device. It is sectional drawing about a part of right inner side plate, center plate, left inner side plate, and cover member in a hydraulic coupling device. It is a figure explaining the action | operation of a 1st relief valve, (A) has shown the state from which the 1st member was pressed by the valve seat, (B) has shown the state from which the 1st member was spaced apart from the valve seat, respectively. . It is a hydraulic circuit diagram which shows the structure of a hydraulic coupling apparatus.

Explanation of symbols

32R Right inner side plate (first plate member)
32L left inner side plate (second plate member)
m1 Moving body accommodation space m2 Right valve hole (first valve hole)
m2a Valve seat m4 Left valve hole (second valve hole)
B1 1st member (moving body)
C1 Second member (moving body)
S1 Return spring (spring member)
h9R communication hole (adjusted pressure supply oil passage)
h9L communication hole (back pressure supply oil passage)
g2R communication groove (relief oil passage)
RV1 First relief valve (pressure regulating valve)
V Four-wheel drive vehicle H Hydraulic coupling device

Claims (7)

The joined first and second plate members, the first valve hole formed extending in the thickness direction of the first plate member, and the first plate member formed extending in the thickness direction of the second plate member. A movable body provided in a movable body accommodation space formed by coaxially joining two valve holes, and the movable body moves in the movable body accommodation space, whereby the first plate In the pressure regulating valve having a configuration in which communication between the adjusted pressure supply oil passage formed in the member and the relief oil passage and the blocking thereof are performed,
2. The pressure regulating valve according to claim 1, wherein the movable body is composed of two members, a first member located on the first valve hole side and a second member located on the second valve hole side. The adjustment pressure supply oil passage extends coaxially with the central axis of the first valve hole, and the relief oil passage extends in a direction substantially perpendicular to the central axis of the first valve hole, and the adjustment pressure supply A tapered valve seat that extends toward the second plate member is formed at a connecting portion between the oil passage and the first valve hole, and the adjusted pressure supply oil is pressed against the valve seat. The pressure regulating valve according to claim 1, comprising a spherical member having an outer diameter capable of blocking communication between a passage and the relief oil passage. The inner diameter of the minimum inner diameter portion of the second valve hole is smaller than the inner diameter of the first valve hole, and the outer diameter of the second member is slightly smaller than the inner diameter of the minimum inner diameter portion of the second valve hole. The pressure regulating valve according to claim 2, comprising a rod-shaped member having A back pressure supply oil passage that is connected to the second valve hole is formed in the second plate member, and the second member receives the pressure in the back pressure supply oil passage and always keeps the first member in the valve. 4. The pressure regulating valve according to claim 2, wherein the pressure regulating valve is urged toward the seat side and communication between the back pressure supply oil passage and the second valve hole is always cut off. 5. 2. The first member is urged by a spring member provided in the second valve hole in a direction that always blocks communication between the adjustment pressure supply oil passage and the relief oil passage. The pressure regulation valve in any one of -4. A hydraulic coupling device comprising the pressure regulating valve according to any one of claims 1 to 5,
A first vane pump and a second vane pump, the rotation shafts of which are arranged coaxially;
A discharge port communication oil passage communicating the discharge ports of both the vane pumps;
A suction port communication oil passage for communicating the suction ports of the two vane pumps;
The first plate member is a side plate of the first vane pump, the second plate member is a side plate of the second vane pump, and the adjustment pressure supply oil passage formed in the first plate member is the The hydrostatic fluid is connected to the discharge port or the suction port of the first vane pump, and the back pressure supply oil passage formed in the second plate member is connected to the discharge port or the suction port of the second vane pump. Rick coupling device. A power transmission device for a four-wheel drive vehicle having left and right main drive wheels and left and right sub drive wheels,
The hydraulic coupling device according to claim 6,
The cam rings of the first vane pump and the second vane pump are driven by a prime mover together with the left and right main drive wheels, and the rotors of the first vane pump and the second vane pump are connected to the axles of the left and right auxiliary drive wheels. A power transmission device for a four-wheel drive vehicle.

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