JP5211385B2 - Hydraulic continuously variable transmission - Google Patents

Description

  The present invention relates to a hydraulic continuously variable transmission that is used in industrial machines, vehicles, and the like and can be widely used in various industrial fields, and particularly relates to a relief valve that is applied to the hydraulic continuously variable transmission.

  Conventionally, a hydraulic pump unit having a first plunger and a first swash plate with which the first plunger abuts, and a hydraulic motor unit having a second plunger and a second swash plate with which the second plunger abuts are input. A hydraulic type that is arranged in front and rear in the axial direction of the input shaft with a cylinder block fitted on the shaft interposed therebetween, and is provided with a pair of main oil passages that communicate between the first plunger and the second plunger. In a continuously variable transmission, a technique related to a relief valve used in the hydraulic continuously variable transmission is known (see, for example, Patent Document 1).

  In this technique, the relief valve is connected to a servo mechanism for changing the inclination angle of the first swash plate, and hydraulic oil discharged from the servo mechanism through the relief valve is used for cooling the first swash plate. Thus, the relief valve is configured by sequentially accommodating the valve body, the spring member, and the locking member in the through hole of the housing of the hydraulic continuously variable transmission. One end of the spring member is fixed to the locking member, while the other end of the spring member holds the valve body, and the valve body is in the middle of the through hole by the elastic force of the spring member. The through-hole is closed by being brought into contact with the stepped portion in a biased state, whereby the relief valve is closed.

  Such a relief valve can also be connected to the charge circuit of the main oil passage, and the hydraulic oil discharged from the charge circuit via the relief valve is discharged to the first swash plate as in the case of connecting to the servo mechanism. It can be used for cooling.

JP 2008-128469 A

  However, in the relief valve having the structure as described above, when the valve is closed or when the pressure of the hydraulic oil in the primary oil passage rises, the valve body separates from the step portion against the elastic force of the spring member. If a disturbance such as oil pressure fluctuation occurs in the primary oil passage when the valve is opened, unstable operation such as valve action or abnormal pulsation occurs due to self-excited vibration, reducing the reliability of the relief operation. There was a problem of doing.

  Furthermore, in the relief valve, the pressure increasing from the minimum flow rate to the maximum flow rate, the so-called override pressure cannot be set small, and the pressure loss of the relief valve is large, so the system efficiency of the entire hydraulic circuit is poor. was there.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
That is, in claim 1, a hydraulic pump unit having a hydraulic pump part having a first plunger and a first swash plate with which the first plunger abuts, and a hydraulic pressure having a second plunger and a second swash plate with which the second plunger abuts. A motor unit is disposed in front and rear in the axial direction of the input shaft across a cylinder block fitted to the input shaft, and the cylinder block has a pair of main oil passages communicating between the first plunger and the second plunger The main oil passage is provided with a charge circuit, a relief valve is connected to the charge circuit, and a primary oil passage from the charge circuit is provided in the sleeve of the relief valve. A primary pressure chamber communicating with the inlet port through the inlet port, and a secondary pressure chamber communicating with the secondary oil passage to the oil reservoir through the discharge port. In the valve seat A valve body portion that connects and disconnects between the primary pressure chamber and the secondary pressure chamber, and a first sliding portion that is on one end side of the valve body and defines the primary pressure chamber between the valve body portion And a second sliding portion that is on the other end side of the valve body and defines the secondary pressure chamber between the valve body portion, the second sliding portion and the first sliding portion are The damper chamber is slidably fitted into the sleeve, and a damper chamber communicating with the primary oil passage through the pore is formed in the sleeve opposite to the primary pressure chamber with the first sliding portion interposed therebetween. On the other hand, the second sliding portion is formed with a pressure receiving portion for receiving the pressure of the hydraulic oil flowing into the secondary pressure chamber from the primary pressure chamber.
According to a second aspect of the present invention, a spring chamber is formed in the second sliding portion. The spring chamber houses a spring member for biasing the valve body in a valve closing direction in which the valve body portion is seated on the valve seat portion. The chamber is used for at least a part of a communication oil passage from the secondary pressure chamber to the discharge port.
In claim 3, the first swash plate is configured to be movable to form a movable swash plate, the secondary oil passage is formed in a swash plate holder that supports the movable swash plate from the rear surface, The side oil passage is composed of an inflow oil hole into which the working oil from the discharge port flows, and a branch oil passage that guides the operating oil from the inflow oil hole to a predetermined position of the movable swash plate. .
In claim 4, the first swash plate is configured to be movable to form a movable swash plate, and a swash plate holder that supports the movable swash plate from the rear surface is further supported by the housing from the rear surface, While drilling a through-hole consisting of a two-stage large-diameter hole and a small-diameter hole whose diameter decreases toward the rear, the sleeve has a large-diameter portion having the secondary pressure chamber therein, and a larger-diameter portion than the large-diameter portion. By forming a small-diameter portion having a small outer diameter and having the primary pressure chamber inside, the relief valve can be inserted into the through-hole from the front side of the housing with the small-diameter portion first. It constitutes.
In Claim 5, the said primary side oil path and the secondary side oil path are arrange | positioned on the same shaft center of a relief valve.

Since this invention was comprised as mentioned above, there exists an effect shown below.
That is, according to claim 1, the hydraulic oil in the damper chamber enters and exits the primary oil passage through the pores, thereby acting as a resistance against the movement of the valve body, and the valve body at the time of opening or closing the valve body Rapid movement can be suppressed, and unstable operation such as valve pulsation or abnormal pulsation due to self-excited vibration can be suppressed, and the reliability of relief operation can be improved. In addition, the hydraulic oil that has flowed into the secondary pressure chamber from the time it is opened to the time it closes can also apply lift to the valve body through the pressure receiving part, The valve opening operation can be facilitated, the override pressure can be reduced, the pressure loss of the relief valve can be reduced, and the system efficiency of the entire hydraulic circuit can be improved.
According to the second aspect, the number of parts for the communication oil passage from the secondary pressure chamber to the discharge port can be reduced, and the relief valve can be made compact and the parts cost can be reduced.
According to the third aspect, the hydraulic oil from the discharge port can be simultaneously supplied to a plurality of appropriate portions of the movable swash plate through the branch oil passage, and the hydraulic oil can be supplied even if the discharge pressure from the discharge port is low. Can be supplied only by its own weight, and the cooling efficiency of the movable swash plate can be greatly improved.
According to the fourth aspect, the distance from the through hole to the outer peripheral surface of the housing, that is, the thickness of the outer peripheral corner portion of the housing can be increased on the rear surface of the housing, and the outer peripheral corner portion is damaged by an external load or impact. In addition to improving the service life of the parts by preventing the deformation and deformation, the range of attachment of the relief valve to the housing can be expanded, and the design flexibility of the hydraulic continuously variable transmission can be increased.
According to the fifth aspect, the change in the flow direction of the hydraulic oil can be minimized, the pressure loss of the relief valve can be reduced, and the system efficiency of the entire hydraulic circuit can be improved. Furthermore, the relief valve can be accommodated in the middle part of the straight external pipe, and the range of the mounting position of the relief valve can be expanded to increase the design freedom of the hydraulic continuously variable transmission.

1 is a front perspective view showing the overall configuration of a hydraulic continuously variable transmission according to the present invention. Similarly, it is a side partial sectional view. It is a side view similarly. Similarly it is a rear view. It is side surface sectional drawing of a relief valve. It is a rear perspective view of a swash plate holder. It is also a front view. It is side surface sectional drawing of a check relief valve. Similarly, FIG. 9A is a side sectional view showing an operating state of the check relief valve, FIG. 9A is a side sectional view showing a valve opening state of the check valve body, and FIG. 9B is a valve opening state of the relief valve body. It is side surface sectional drawing shown. It is a side view of a tilting actuator. It is a hydraulic circuit diagram of a hydraulic continuously variable transmission. It is a figure which shows the attachment structure of another form of a relief valve, Comprising: Fig.12 (a) is side sectional drawing of the attaching part of a relief valve, FIG.12 (b) is a hydraulic circuit diagram similarly. It is a side view which shows another form of a tilting actuator. It is a side view which shows another form of a spool valve. It is a hydraulic circuit diagram which shows the alternative structure of a check relief valve.

Hereinafter, embodiments of the present invention will be described in detail.
In addition, the direction shown by the arrow F in the figure is the forward direction of the hydraulic continuously variable transmission 1, and the positions and directions of the members described below are based on this forward direction.

First, the overall configuration of a hydraulic continuously variable transmission 1 according to the present invention will be described with reference to FIGS.
The hydraulic continuously variable transmission 1 is disposed on an input shaft 2 connected to an engine (not shown), and on the front end side of the input shaft 2, that is, on the same side as the input side to the input shaft 2, An output case 3 connected to an output shaft (not shown) is disposed. A cylinder block 4 is fitted on the input shaft 2 so as to be relatively non-rotatable by a spline at a front and rear center, and a hydraulic motor section 6 is provided on the input side of the input shaft 2 with the cylinder block 4 interposed therebetween. On the other hand, a hydraulic pump unit 5 is arranged on the side opposite to the input side across the cylinder block 4.

  The hydraulic pump unit 5 includes a housing 7 that is engaged with the rear end of the input shaft 2, a swash plate holder 8 that is fastened and fixed to the front portion of the housing 7 with bolts, and a front end of the swash plate holder 8. A first swash plate 10 in which a support shaft 10c is slidably supported via a metal bearing 9 in a substantially semicircular recess 8a, and a shoe 11 slidably provided on the first swash plate 10. A first plunger 12 connected to the shoe 11 by a spherical universal joint, and a first plunger hole 13 for disposing the first plunger 12 in the front cylinder block 4 so as to freely enter and exit from the rear are provided.

  The rear end side of the first plunger 12 protrudes from the rear surface of the cylinder block 4 toward the first swash plate 10 by the elastic force of the spring member 14 accommodated in the first plunger hole 13 and comes into contact therewith. Thus, when the cylinder block 4 rotates, the first plunger 12 can reciprocate by the pressing force received from the swash plate surface 10b of the first swash plate 10.

  Further, between the input shaft 2 and the swash plate holder 8, a sleeve 16 fitted to the input shaft 2, a roller bearing 17 on the outer periphery of the sleeve 16, and a roller bearing 18 for radial and thrust loads are interposed. A nut 19 for preventing the roller bearing 18 from being detached is provided at the rear end of the input shaft 2. The cylinder block 4 on the input shaft 2 is provided with the same number of first spool valves 20 as the first plungers 12.

  The hydraulic motor unit 6 is provided with the output case 3, a second swash plate 22 that is fastened and fixed to the output case 3 by bolts 21 and has a constant inclination angle, and is slidably provided on the second swash plate 22. A shoe 23, a second plunger 24 connected to the shoe 23 by a spherical universal joint, and a second plunger hole 25 for disposing the second plunger 24 in the cylinder block 4 from the front are provided.

  The front end side of the second plunger 24 protrudes from the front surface of the cylinder block 4 toward the second swash plate 22 by the elastic force of the spring member 26 accommodated in the second plunger hole 25 and comes into contact therewith. Thus, a rotational force can be applied to the inclined second swash plate 22 by the reciprocating motion of the second plunger 24. The second swash plate 22, the output case 3 fastened and fixed to the second swash plate 22, and an output shaft (not shown) are integrally arranged on the input shaft 2 so as to be rotatable. ing.

  Further, a roller bearing 28 and a radial and thrust load roller bearing 29 are interposed between the input shaft 2 and the second swash plate 22, and a nut 30 for preventing the roller bearing 29 from coming off. Is provided at the front end of the input shaft 2. The cylinder block 4 on the input shaft 2 is provided with the same number of second spool valves 31 as the second plungers 24, similarly to the hydraulic pump unit 5.

  In the cylinder block 4, the first plunger hole 13 and the second plunger hole 25 are alternately formed on the same circumference of the rotation center of the cylinder block 4, and the input shaft 2 is connected to the cylinder block 4. In the shaft hole 4a to be inserted, a first oil passage 41 and a second oil passage 42 having a ring groove shape are formed in order from the rear.

  Further, the cylinder block 4 also includes first valve holes 32 and second valve holes 33 that accommodate the first spool valve 20 and the second spool valve 31, respectively, on the same circumference of the rotation center of the cylinder block 4. Is formed.

  In addition, both the first oil passage 41 and the second oil passage 42 are communicated with the first plunger hole 13 via the first valve hole 32 of the first spool valve 20, and the second spool valve 31. The second plunger hole 25 communicates with the second valve hole 33.

  On the other hand, a disc-shaped engaging portion 111 is formed at the front portion of the guide shaft 110 protruding rearward from the first spool valve 20, and the disc-shaped engaging portion 111 protrudes from the rear surface of the cylinder block 4. The ring-shaped first spool cam 34 is engaged with the cam groove 34 a connected and fixed to the tip of the swash plate holder 8.

  Thus, when the cylinder block 4 makes one rotation, the engaging portion 111 moves along the cam groove 34a, and the first spool valve 20 reciprocates and slides in the first valve hole 32 so that the first oil passage 41 or An opening / closing operation is performed on the second oil passage 42 so that the first plunger hole 13 communicates with the first oil passage 41 or the second oil passage 42 alternately.

  Similarly, a disc-shaped engaging portion 113 is formed at the front portion of the guide shaft 112 protruding forward from the second spool valve 31, and the engaging portion 113 protrudes from the front surface of the cylinder block 4, The second swash plate 22 is engaged with a cam groove 35a of a ring-shaped second spool cam 35 connected and fixed to the rear end.

  As a result, when the cylinder block 4 rotates once, the engaging portion 113 moves along the cam groove 35a, and the second spool valve 31 reciprocates and slides in the second valve hole 33 so that the first oil passage 41 or An opening / closing operation with respect to the second oil passage 42 is performed so that the second plunger hole 25 communicates with the first oil passage 41 or the second oil passage 42 alternately.

  In the configuration as described above, in the hydraulic continuously variable transmission 1, the first plunger hole 13 and the second plunger hole 25 are connected to the first oil passage by the spool valves 20 and 31 that slide back and forth according to the spool cams 34 and 35. The fluid is connected at a predetermined rotational position through a closed circuit composed of 41 and the second oil passage 42, and the first swash plate 10 receives the first force from the swash plate surface 10 b as the input shaft 2 rotates. When one plunger 12 reciprocates, the fluid-connected second plunger 24 also reciprocates, and a predetermined rotational force is applied from the second plunger 24 to the inclined second swash plate 22.

  Further, in the hydraulic continuously variable transmission 1, the hydraulic pump unit 5 having the first plunger 12 and the first swash plate 10 with which the first plunger 12 abuts, the second plunger 24, and the second plunger 24 include A hydraulic motor unit 6 having a second swash plate 22 that abuts is disposed in the axial direction of the input shaft 2 with the cylinder block 4 fitted to the input shaft 2 interposed therebetween. Since the first oil passage 41 and the second oil passage 42 which are a pair of main oil passages communicating between the plunger 12 and the second plunger 24 are provided, the input shaft 2 to the hydraulic continuously variable transmission 1 and The axial length of the hydraulic continuously variable transmission 1 can be shortened by making the output shaft (not shown) into a double structure inside and outside, and the hydraulic continuously variable transmission 1 can be reduced in size and weight. It has become.

Next, the hydraulic circuit configuration of the hydraulic continuously variable transmission 1 having the overall configuration as described above will be described with reference to FIGS. 2 to 4, 10, and 11.
The hydraulic circuit is provided with a charge circuit 52 and a swash plate angle control mechanism 53.

  In the charge circuit 52, a hydraulic oil charge oil passage 43 is formed in the central portion of the input shaft 2, and a first oil passage 43 is provided between the charge oil passage 43 and the first oil passage 41. A check relief valve 36 is interposed, and a second check relief valve 37 is interposed between the charge oil passage 43 and the second oil passage 42. On the other hand, the charge oil passage 43 communicates with the discharge side of the charge pump 38 via the external pipe 40. As a result, the hydraulic oil from the charge pump 38 is supplied to the check relief valves 36 and 37 via the external pipe 40 and the charge oil passage 43.

  Then, as will be described in detail later, when the hydraulic oil in the first oil passage 41 and the second oil passage 42 is insufficient and the pressure is reduced, the check relief valves 36 and 37, when the pressure decreases. It functions as a check valve for supplying hydraulic oil to the second oil passage 42 from the charge oil passage 43, and conversely, if the pressure of the hydraulic oil in the first oil passage 41 and the second oil passage 42 increases excessively, It functions as a relief valve that discharges hydraulic oil from the first oil passage 41 and the second oil passage 42 to the charge oil passage 43.

  Further, the primary side of the relief valve 50 is connected to the middle portion of the external pipe 40 communicating with the charge oil path 43 through the external pipe 86 and the internal oil path 48, and the secondary side of the relief valve 50 is connected. The side communicates with an oil sump 51 formed on the rear surface of the first swash plate 10 via a relief oil passage 49 described later. As a result, the pressure of the hydraulic oil supplied from the charge pump 38 into the charge oil passage 43 can be maintained at a predetermined set pressure.

  In addition, a plurality of lubricating oil passages 44, 45 are branched in the radial direction of the charge oil passage 43, and the outer ends of the lubricating oil passages 44, 45 are connected to an oil sump 46 in the rotating portion of the hydraulic pump unit 5, The oil motor 47 communicates with an oil sump 47 in the rotating portion. As a result, excess hydraulic oil in the charge oil passage 43 can be supplied as lubricating oil for the hydraulic continuously variable transmission 1.

The swash plate angle control mechanism 53 will be described.
The tilt angle of the first swash plate 10 can be changed by the tilt actuator 54. The tilting actuator 54 includes a cylinder 7a formed in the front-rear direction at the lower part of the housing 7, a cylinder lid 104 closing the front opening of the cylinder 7a, and a piston 55 inserted in the cylinder 7a so as to be slidable in the front-rear direction. It consists of.

  The piston 55 includes a rod part 55b on the shaft center and a diameter-enlarged part 55a formed at the rear end of the rod part 55b, and the rod part 55b can slide the cylinder lid 104. A locking hook 56 is fixed by a piston pin 105 at the front end of the front end.

  The locking hook 56 is engaged with a locking portion 10 a extending forward from the lower portion of the first swash plate 10, and the piston 55 is moved back and forth in the front-rear direction by the reciprocating sliding operation. The swash plate 10 is tilted back and forth around a tilt center axis (not shown).

  On the other hand, a front oil chamber 57 is constituted by the front end face of the enlarged diameter portion 55a and the cylinder 7a, and a rear oil chamber 58 is constituted by the rear end face of the enlarged diameter portion 55a and the cylinder 7a. 57 and 58 are connected to a 2-port 3-position tilt switching valve 61 via oil passages 59 and 60, respectively.

  The tilt switching valve 61 is provided with a reciprocally slidable spool 61a, and a bottom oil chamber 61b provided at one end of the spool 61a communicates with a servo oil passage 64 through a pilot oil passage 62, The servo oil passage 64 is communicated with the discharge side of the servo pump 39 via the external pipe 63. A proportional adjustment valve 65 is interposed in the middle of the pilot oil passage 62 so that the pressure of the hydraulic oil in the bottom oil chamber 61b can be adjusted.

  On the other hand, a spring member 66 provided on the other end side of the spool 61a is linked to the first swash plate 10 via a feedback link 67, and even if the position of the first swash plate 10 depends on the position of the spool 61a. The position is switched. Here, the solenoid of the proportional adjustment valve 65 is connected to a controller 75 via a cable 77, and a speed change operation lever 76 is connected to the controller 75. In response to this, a shift signal is transmitted from the controller 75 to the solenoid.

  Further, the tilt switching valve 61 is formed with a pilot port 68 for supplying pilot hydraulic pressure and a drain port 69, and the pilot port 68 communicates with the servo oil passage 64, while the drain port 69 is connected to the oil passage. The oil reservoir 71 communicates with the oil reservoir 71.

  Accordingly, by operating the speed change lever 76 to transmit a speed change signal from the controller 75 to the proportional adjustment valve 65 and setting the tilt switching valve 61 to either of the positions 72 and 74, the oil chambers 57 and 58 are controlled. One of them is supplied with hydraulic oil from the servo oil passage 64, and the other is discharged into the oil reservoir 71, whereby a differential pressure is generated in the hydraulic oil in the oil chambers 57 and 58, and the piston 55. Slides back and forth in the front-rear direction, and the first swash plate 10 tilts back and forth.

  Further, when the tilt switching valve 61 is set to the position 73, the communication between the servo oil passage 64 and the oil reservoir 71 is cut off in both of the oil chambers 57 and 58, thereby stopping the forward and backward sliding of the piston 55. Thus, the first swash plate 10 is held at a predetermined inclination angle. That is, the inclination angle of the first swash plate 10 can be set to a predetermined inclination angle after steplessly changing.

  In the configuration as described above, when the tilt actuator 54 is operated via the proportional adjustment valve 65 and the tilt angle of the first swash plate 10 is changed steplessly, the first plunger reciprocatingly moves in the first plunger hole 13. The amplitude amount of the plunger 12 changes, and the amount of hydraulic oil supplied and discharged changes with the reciprocation.

  Then, the amount of hydraulic oil supplied to and discharged from the second plunger hole 25 connected to the first plunger hole 13 via the first oil path 41 or the second oil path 42 also changes, and the second plunger 24 The amount of amplitude also changes. As a result, the rotation speed and rotation direction of the second swash plate 22 in contact with the second plunger 24 are variable, and a continuously variable transmission power from an output shaft (not shown) that rotates integrally with the second swash plate 22. Can be output.

Next, the relief valve 50 will be described with reference to FIGS. 3 to 5, 11, and 12.
As shown in FIGS. 3 to 5 and 11, the relief valve 50 is connected to a relief oil passage 49 and connected to a spring holding member 79 having a spline on the outer periphery and a rear end of the spring holding member 79. The sleeve 80 includes a valve body 81 that is slidably inserted into the sleeve 80, and a spring member 82 that is interposed between the valve body 81 and the spring holding member 79.

  The spring holding member 79, the sleeve 80, the valve body 81, and the spring member 82 are disposed on the same axis, and are inserted into a through hole 78 that is perforated in the front-rear direction at the top of the housing 7.

  The through-hole 78 is formed with a large-diameter hole 78a and a small-diameter hole 78b having an inner diameter smaller than that of the large-diameter hole 78a before and after the large-diameter hole 78a and the small-diameter hole 78b. A stopper 78c having the smallest inner diameter is formed.

  The spring holding member 79 is inserted into the front end portion of the large-diameter hole 78a and is spline-fitted. A discharge hole 83 is provided on the axial center of the spring holding member 79, and a discharge port 83a and a spring receiving hole 83b having a larger inner diameter than the discharge port 83a are formed in the discharge hole 83 in the front and rear. Is done.

  The sleeve 80 is formed with a large diameter portion 84 and a small diameter portion 85 having an outer diameter smaller than that of the large diameter portion 84 at the front and rear. Of these, the large diameter portion 84 is inserted and fitted from the center portion to the rear end portion of the large diameter hole 78a of the through hole 78, and a shaft center hole 84a is drilled in the large diameter portion 84. The front end of the hole 84 a is opened and connected to the discharge hole 83 of the spring holding member 79.

  The small diameter portion 85 is bored with an axial hole 85a having an inner diameter smaller than that of the axial hole 84a, and the rear end thereof is closed to form a fine hole 93 on the axial center. A valve seat 80a for seating the valve body 81 when the valve is closed is provided at the corner of the inner stepped portion between the shaft hole 85a and the shaft hole 84a.

  Furthermore, the outer diameter of the small diameter portion 85 is set to be smaller than the inner diameter of the small diameter hole 78b, and the internal oil passage that is the primary oil passage is formed in the gap space between the small diameter portion 85 and the small diameter hole 78b. 48 is formed and connected to the external pipe 86. In the internal oil passage 48, a plurality of inlet ports 85b provided on the same outer periphery at the small diameter portion 85 near the stopper 78c are opened.

  Further, the valve body 81 is formed with a conical valve body part 87 closed rearward at a substantially central position in the front-rear direction so as to be able to contact and separate from the valve seat part 80a. Is formed with a first sliding portion 88 slidably fitted to the inner surface of the axial hole 85 a of the sleeve 80 via the stem portion 90.

  Due to the first sliding portion 88, the inside of the axial hole 85 a of the sleeve 80 is defined as a primary pressure chamber 91 between the valve body portion 87 and a damper chamber 94 between the rear end of the sleeve 80. Is done. The primary pressure chamber 91 and the damper chamber 94 are communicated with the internal oil passage 48 through the inlet port 85b and the pore 93, respectively.

  The front end side of the valve body portion 87 is slidably fitted to the inner surface of the axial center hole 84a of the sleeve 80 via a connecting portion 100 having an outer diameter substantially coincident with the front end of the valve body portion 87. A second sliding portion 89 is formed. The second sliding portion 89 defines a secondary pressure chamber 92 between the valve body portion 87 and the shaft center hole 84 a of the sleeve 80. The front wall of the secondary pressure chamber 92 is constituted by a ring-shaped pressure receiving portion 99 at a step portion between the second sliding portion 89 and the connecting portion 100.

  Inside the second sliding portion 89, a spring chamber 95 having an inner diameter substantially coincident with the spring receiving hole 83b of the spring holding member 79 is formed on the same axis, and the spring chamber 95 and the spring receiving hole 83b are formed. The spring member 82 is interposed in a compressed state. The elastic force of the spring member 82 causes the valve body portion 87 to be seated on the valve seat portion 80a. The valve body 81 is constantly energized.

  Further, a vertical hole 96 having an inner diameter smaller than that of the spring chamber 95 is formed on the same axis at the rear end of the spring chamber 95, and a plurality of lateral holes are radially formed from the rear portion of the vertical hole 96 in the radial direction. A hole 97 is formed, and the lateral hole 97 is opened in the secondary pressure chamber 92.

  As a result, the secondary pressure chamber 92 is communicated with the discharge port 83a via a communication oil passage 98 including a horizontal hole 97, a vertical hole 96, a spring chamber 95, a spring receiving hole 83b, and the like. 83a communicates with the oil reservoir 51 through the relief oil passage 49 as described above. The relief oil passage 49 and the internal oil passage 48 are arranged on the same axis of the relief valve 50.

  In the above configuration, the hydraulic oil in the charge oil passage 43 is guided from the external pipe 40, the external pipe 86, and the internal oil path 48 to the primary pressure chamber 91 through the inlet port 85b. If the pressure of the hydraulic oil in the chamber 91 is lower than the set pressure corresponding to the elastic force of the spring member 82, the valve body 81 is maintained in a closed state, and the valve body portion 87 is placed on the valve seat portion 80 a of the sleeve 80. Sitting.

  Then, when the pressure of the hydraulic oil in the charge oil passage 43 increases and the pressure of the hydraulic oil in the primary pressure chamber 91 becomes higher than the set pressure, as shown in FIG. The valve body portion 87 moves away from the valve seat portion 80a of the sleeve 80 and is opened. Then, the hydraulic oil in the primary pressure chamber 91 flows into the secondary pressure chamber 92 and is discharged to the discharge port 83a through the communication oil passage 98.

  At this time, the hydraulic oil that has flowed into the secondary pressure chamber 92 from the primary pressure chamber 91 initially flows forward substantially parallel to the shaft center, but when it collides with the pressure receiving portion 99 in the middle, the direction is 90 degrees inside. Instead, it flows into the lateral hole 97. Accordingly, in the valve open state, the pressure of the hydraulic oil can be applied not only to the valve body portion 87 but also to the pressure receiving portion 99, and a large lift is applied to the valve body 81.

  Further, as the valve element 81 moves when the valve element 81 is opened or closed, the hydraulic oil stored in the damper chamber 94 is again supplied to and discharged from the internal oil passage 48 through the pores 93, thereby The damper function which suppresses the movement of 81 can be exhibited.

  That is, it has the hydraulic pump part 5 which has the 1st plunger 12 and the 1st swash plate 10 which this 1st plunger 12 contacts, and the 2nd plunger 24 and the 2nd swash plate 22 which this 2nd plunger 24 contacts. The hydraulic motor unit 6 is arranged in front and rear in the axial direction of the input shaft 2 with a cylinder block 4 fitted to the input shaft 2 interposed therebetween, and the cylinder block 4 is provided between the first plunger 12 and the second plunger 24. In the hydraulic continuously variable transmission 1 provided with a first oil passage 41 and a second oil passage 42 which are a pair of main oil passages communicating with each other, the first oil passage 41 and the second oil passage 42 are connected to a charge circuit 52. A relief valve 50 is connected to the charge circuit 52, and the sleeve 80 of the relief valve 50 communicates with an internal oil passage 48 that is a primary oil passage from the charge circuit 52 via an inlet port 85b. Primary pressure to 91, and a secondary pressure chamber 92 communicating with a relief oil passage 49, which is a secondary oil passage to the oil reservoir 51, via a discharge port 83a. The valve body 81 of the relief valve 50 includes the sleeve A valve body portion 87 that is in contact with and separates from the 80 valve seat portion 80a and connects and disconnects the primary pressure chamber 91 and the secondary pressure chamber 92; and the primary pressure on the rear end side that is one end side of the valve body 81 A first sliding portion 88 that defines the chamber 91 between the valve body portion 87 and a front end side that is the other end side of the valve body 81, and the secondary pressure chamber 92 is disposed between the valve body portion 87 and the valve body portion 87. A second sliding portion 89 defined in the sleeve, and the second sliding portion 89 and the first sliding portion 88 are slidably fitted into the sleeve 80 and the first sliding portion. In the sleeve 80 on the opposite side of the primary pressure chamber 91 across the portion 88, there is provided a damper chamber 94 that communicates with the internal oil passage 48 through the pore 93. Since the second sliding portion 89 is formed with a pressure receiving portion 99 for receiving the pressure of the hydraulic oil flowing from the primary pressure chamber 91 into the secondary pressure chamber 92, the hydraulic oil in the damper chamber 94 is By entering and exiting the internal oil passage 48 through the pores 93, it acts as a resistance to the movement of the valve body 81, and can suppress rapid movement of the valve body 81 at the time of opening or closing the valve. Unstable operation such as valve formation or abnormal pulsation due to vibration can be suppressed, and the reliability of the relief operation can be improved. Further, the hydraulic oil that has flowed into the secondary pressure chamber 92 during the period from when the valve is opened to when the valve is closed can also apply lift to the valve body 81 via the pressure receiving portion 99, and in a large flow rate range. The valve body 81 can be easily opened to reduce the override pressure, the pressure loss of the relief valve 50 can be reduced, and the system efficiency of the entire hydraulic circuit can be improved.

  Further, a spring chamber 95 is formed in the second sliding portion 89 to house a spring member 82 for biasing the valve body 81 in the valve closing direction in which the valve body portion 87 is seated on the valve seat portion 80a. The spring chamber 95 is used in at least a part of the communication oil passage 98 from the secondary pressure chamber 92 to the discharge port 83a, so that the number of parts for the communication oil passage 98 can be reduced, and the relief valve 50 can be made compact and the cost of parts can be reduced.

In addition, the mounting configuration of the relief valve 50 having such a structure to the housing 7 will be described.
As shown in FIGS. 3 to 5, as described above, the through hole 78 for inserting the relief valve 50 is drilled in the front-rear direction in the upper part of the housing 7. 78a, a stopper 78c, and a small diameter hole 78b are formed. On the sleeve 80 that defines the outer shape of the relief valve 50, a large diameter portion 84 and a small diameter portion 85 are formed in order from the front.

  Of these, the outer diameter of the large-diameter portion 84 is substantially the same as the inner diameter of the large-diameter hole 78a, and the large-diameter portion 84 can be inserted into the large-diameter hole 78a. Further, the outer diameter of the small diameter portion 85 is substantially the same as the inner diameter of the stopper 78c, and is set smaller than the inner diameter of the small diameter hole 78b as described above.

  In the configuration as described above, when the relief valve 50 is incorporated into the upper portion of the housing 7, the sleeve 80 is inserted into the through hole 78 with the small diameter portion 85 first, and the large diameter portion 84 is aligned with the large diameter hole 78a. The sleeve 80 is slid rearward, and the outer peripheral corner of the rear end of the large diameter portion 84 of the sleeve 80 is brought into contact with the stopper 78 c of the through hole 78.

  Thereafter, with the first sliding portion 88 first, the valve body 81 is inserted into the axial hole 84a / 85a of the sleeve 80, and the second sliding body 89 is moved along the axial hole 84a while the valve body 81 is moved backward. The valve body portion 87 of the valve body 81 is seated on the valve seat portion 80 a of the sleeve 80.

  Subsequently, after the spring member 82 is inserted into the spring chamber 95 of the valve body 81, the spring holding member 79 is inserted into the large-diameter hole 78a of the through hole 78 from the front to be splined, and then fixed in a ring shape. By the member 160, the spring holding member 79 and the sleeve 80 are sandwiched and fixed between the stoppers 78c, whereby the relief valve 50 is inserted into the through hole 78.

  At this time, the rear portion of the through hole 78 is formed as a small diameter hole 78b having a small inner diameter, and the distance 161 from the through hole 78 to the outer peripheral surface 7b of the housing 7, that is, the thickness of the outer peripheral corner portion 7c of the housing 7 is compared. Can be set larger.

  That is, the first swash plate 10 is configured to be movable to be a movable swash plate, and a swash plate holder 8 that supports the first swash plate 10 from the rear surface is further supported by the housing 7 from the rear surface. Is formed with a through-hole 78 composed of a two-stage large-diameter hole 78a and a small-diameter hole 78b that become smaller in diameter toward the rear, while the sleeve 80 has a large-diameter portion 84 having the secondary pressure chamber 92 therein. And a small-diameter portion 85 having an outer diameter smaller than that of the large-diameter portion 84 and having the primary pressure chamber 91 in the front and rear thereof, the relief valve 50 is disposed in the housing with the small-diameter portion 85 first. 7, the distance 161 from the through hole 78 to the outer peripheral surface 7 b of the housing 7 on the rear surface of the housing 7, that is, the thickness of the outer peripheral corner portion 7 c of the housing 7. Can be thick The outer peripheral corner portion 7c is prevented from being damaged or deformed by an external load or impact, so that the service life of the parts can be improved and the attachment range of the relief valve 50 to the housing 7 can be expanded. The design freedom of the continuously variable transmission 1 can be increased.

Further, another mounting structure of the relief valve 50 will be described.
The hydraulic continuously variable transmission 1A shown in FIG. 12 (b) is different from the hydraulic continuously variable transmission 1 shown in FIG. 11 in that the relief valve 50 of the charge circuit 52 is not located inside the hydraulic continuously variable transmission 1. In the middle of the external pipe 86 located outside.

  As shown in FIG. 12A, the relief valve 50A of the hydraulic continuously variable transmission 1A is inserted into a pipe-shaped valve case 101 and protrudes inward from the inner wall of the valve case 101. The positioning member 116 is inserted into and fixed to the valve case 101 so that the shoulder 80b of the sleeve 80 is brought into contact therewith. Further, in the valve case 101, a connecting oil passage 102 is formed on the primary side of the relief valve 50A, and a relief oil passage 103 is formed on the secondary side of the relief valve 50A. Similar to the relief oil passage 49 and the internal oil passage 48 in the hydraulic continuously variable transmission 1, the connecting oil passage 102 is disposed on the same axis of the relief valve 50A.

  An end portion of an external pipe 86 is screwed into the relief oil path 103 and the connection oil path 102, and the external pipe 86 on the relief oil path 103 side communicates with the oil reservoir 51 and is connected to the connection oil path. The external pipe 86 on the 102 side communicates with the charge oil passage 43 via the external pipe 40, and the pressure of the hydraulic oil supplied from the charge pump 38 into the charge oil passage 43 is predetermined by the relief valve 50A. The set pressure is maintained.

  That is, as described above, the internal oil passage 48 and the connecting oil passage 102 which are the primary oil passages, and the relief oil passage 49 and the relief oil passage 103 which are the secondary oil passages are the same shaft of the relief valves 50 and 50A. Since it is arranged on the center, in both of the hydraulic continuously variable transmissions 1 and 1A, the change in the flow direction of the hydraulic oil can be suppressed to the minimum, the pressure loss of the relief valves 50 and 50A can be reduced, and the hydraulic pressure can be reduced. The system efficiency of the entire circuit can be improved. Further, like the hydraulic continuously variable transmission 1A, the relief valve 50A can be accommodated in the middle portion of the straight external pipe 86, and the range of the mounting position of the relief valve 50 is expanded. The degree of freedom in designing the step transmission 1 can be increased.

Next, a cooling configuration using hydraulic fluid discharged from the relief valve 50 will be described with reference to FIGS.
The relief oil passage 49 connected to the secondary side of the relief valve 50 is formed in the rear part of the swash plate holder 8 that supports the first swash plate 10 slidably by the recess 8a.

  In the swash plate holder 8, the relief oil passage 49 is connected to the front end of the discharge hole 83 of the relief valve 50, and the inflow oil hole 49 a that is closed at the front end through which hydraulic oil flows from the discharge port 83 a and the inflow oil hole 49 a. The branch oil passages 49b and 49c are branched and extended to the left and right, and the discharge holes 49d and 49e are formed at the extending ends of the branch oil passages 49b and 49c, respectively.

  Of these, the branch oil passages 49b and 49c are formed in a groove shape on the rear surface 8b of the swash plate holder 8, and the front oil surface 7d of the housing 7 is brought into contact with the rear surface 8b to be fastened and fixed. The rear sides of 49b and 49c are closed to form sealed passages. Thereby, the hydraulic oil from the relief valve 50 flows through the branch oil passages 49b and 49c from the inflow oil hole 49a without leaking.

  Further, the branch oil passages 49b and 49c gradually descend along the circular shaft hole 8c on the axis of the swash plate holder 8 with the inflow oil hole 49a as the apex, and the discharge holes 49d respectively. -It communicates with 49e. Thereby, the hydraulic oil from the relief valve 50 gradually flows down in the branch oil passages 49b and 49c by its own weight, and reaches the discharge holes 49d and 49e.

  The discharge holes 49d and 49e are formed so as to penetrate the swash plate holder 8 in the front-rear direction, and at the tip, the left and right support shafts 10c of the first swash plate 10 slide with the recesses 8a of the swash plate holder 8. Opened in the part to be. As a result, the hydraulic oil from the relief valve 50 is preferentially guided to a position where the sliding is intense and the heat generation is large, and even if the heat generation position is a plurality of positions, it can be guided simultaneously.

  That is, the first swash plate 10 is configured to be movable to form a movable swash plate, and a relief oil passage 49 that is the secondary oil passage is formed in the swash plate holder 8 that supports the movable swash plate from the rear surface. The relief oil passage 49 includes an inflow oil hole 49a into which hydraulic oil from the discharge port 83a flows, and a predetermined position of the movable swash plate from the inflow oil hole 49a. In this embodiment, the support shaft 10c slides with the recess 8a. Since the branch oil passages 49b and 49c guide the hydraulic oil so as to flow down to the moving position, the hydraulic oil from the discharge port 83a is supplied to a plurality of locations on the movable swash plate via the branch oil passages 49b and 49c. While being able to supply simultaneously, even if the discharge pressure from a discharge port is low, hydraulic oil can be supplied only with its own weight, and the cooling efficiency of a movable swash plate can be improved significantly.

  Next, the check relief valves 36 and 37 will be described with reference to FIGS. 2, 8, 9, 11, and 15. Since both check relief valves 36 and 37 have substantially the same structure, only the second check relief valve 37 of one check relief valve will be described in this embodiment, and the description of the first check relief valve 36 will be omitted.

  2, 8, and 11, the second check relief valve 37 includes a ring-shaped valve seat 121, a check valve body 122 that is inserted into the valve seat 121, a valve holding member 123, and a spring holding The member 124 includes a relief valve element 127 inserted into the check valve element 122, a first spring member 126, and a second spring member 128.

  The valve seat 121, the check valve body 122, the valve holding member 123, the spring holding member 124, the relief valve body 127, the first spring member 126, and the second spring member 128 are all arranged on the same axis. It is inserted into a valve hole 129 formed in the diameter direction of the input shaft 2.

  In the valve hole 129, the bottom end is formed by closing the lower end, while the supply / exhaust port 129a is formed by opening the upper end. The supply / exhaust port 129a is connected to the second oil passage 42, and the valve seat 121 is inserted and fixed in the valve hole 129 near the supply / exhaust port 129a.

  An upper portion of the check valve body 122 is inserted in the valve seat 121, and a conical valve body portion 130 closed downward is formed in the upper portion, and the valve body portion 130 is formed in the valve seat 130. The valve seat part 121a provided in the corner | angular part of the inner step part of 121 is comprised so that contact / separation is possible.

  The lower part of the check valve body 122 is inserted and connected to the valve holding member 123, and the lower part of the valve holding member 123 is inserted and connected to the spring holding member 124. An object (hereinafter referred to as “sliding body”) 142 is configured. The lower portion of the sliding body 142 is inserted in the valve hole 129 in the cylinder portion 129b below the charge oil passage 43 so as to be vertically slidable.

  Further, an upper hole 136 and a lower hole 137 having an inner diameter larger than that of the upper hole 136 are bored in the check valve body 122 in the vertical direction, and a lower end of the lower hole 137 is opened to open the valve. Connected to the holding member 123. On the other hand, the upper end of the upper hole 136 is reduced in diameter by one step and then connected to a fine hole 131 pierced on the axial center at the top of the check valve body 122, and the upper hole 136 is connected via the fine hole 131. It communicates with the supply / exhaust port 129a.

  A through hole 138 is formed in the valve holding member 123 in the vertical direction, and an upper portion of the through hole 138 is expanded in diameter so as to be screwed into the lower portion of the check valve body 122 from the outside. As described above, the valve holding member 123 is connected to the check valve body 122. An inner spring chamber 134 having substantially the same inner diameter is formed from the lower hole 137 of the check valve body 122 to the lower portion of the through hole 138 of the valve holding member 123, and the relief spring is formed in the inner spring chamber 134. The valve body 127 and the second spring member 128 are accommodated.

  Further, flow holes 133 and 133 are formed in the side surface of the through hole 138 in the front-rear direction, and the inner spring chamber 134 is communicated with the charge oil passage 43 through the flow holes 133 and 133.

  The spring holding member 124 has a cylindrical shape closed downward, and includes a cylindrical portion 124a and a bottom portion 124b, and the cylindrical portion 124a is fitted and fixed to the lower portion of the valve holding member 123. As described above, the spring holding member 124 is connected to the valve holding member 123.

  In this way, the check valve body 122 can be opened and closed with respect to the valve seat 121, and the sliding body 142 provided with the check valve body 122 can slide up and down in the valve hole 129.

  Further, an oil chamber 135 is formed on the opposite side of the inner spring chamber 134 across the bottom portion 124 b of the spring holding member 124, that is, between the bottom portion 124 b and the bottom surface portion 129 c of the valve hole 129. The oil chamber 135 and the inner spring chamber 134 are communicated with each other through a pore 132 formed on the axis of the bottom portion 124b.

  The first spring member 126 includes a lower surface of the valve seat 121 and the valve holding member 123 in an outer spring chamber 143 surrounded by the check valve body 122, the valve holding member 123, the valve seat 121, and the valve hole 129. Between the outer peripheral corner portion 123a and the outer peripheral corner portion 123a in a compressed state. And, by the elastic force of the first spring member 126, the check valve body 122 is always urged in the valve closing direction in which the valve body 130 is seated on the valve seat 121a, in the present embodiment, downward. Yes.

  Further, the lower part of the outer spring chamber 143 is also communicated with the charge oil passage 43 in the same manner as the flow holes 133 and 133.

  The relief valve element 127 is disposed inside the check valve element 122 and on the same axis, and the relief valve element 127 and the check valve element 122 form a coaxial double structure. .

  Further, a conical valve body portion 139 that is closed upward is formed in the upper half of the relief valve body 127 so that the valve body portion 139 can contact and separate from the valve seat portion 141 of the check valve body 122. It is configured. Here, the valve seat 141 is provided at the corner of the stepped portion between the upper hole 136 and the lower hole 137 of the check valve body 122. On the other hand, a rod-shaped locking portion 140 having an outer diameter smaller than the lower end of the valve body portion 139 is formed in the lower half portion of the relief valve body 127, and the second spring member is formed on the locking portion 140. The upper end of 128 is fitted and fixed.

  In the inner spring chamber 134, the second spring member 128 is interposed in a compressed state between the locking portion 140 of the relief valve body 127 and the bottom portion 124b of the spring holding member 124. Then, by the elastic force of the second spring member 128, the relief valve element 127 is always urged in the valve closing direction in which the valve element portion 139 is seated on the valve seat portion 141, in this embodiment, upward. .

  In the above configuration, in the steady state, as shown in FIG. 8, the valve body portion 139 of the relief valve body 127 urged by the second spring member 128 is placed on the valve seat portion 141 of the check valve body 122. The upper hole 136 that is seated and communicates with the pore 131 is closed.

  As a result, the inner spring chamber 134 is closed from the upper hole 136 and closed, and the pressure of the hydraulic oil in the charge oil passage 43 acts on the inner spring chamber 134 via the flow holes 133 and 133. The sliding body 142 slides. At the same time, the hydraulic fluid that has flowed from the charge oil passage 43 through the flow holes 133 and 133 into the inner spring chamber 134 can also flow into the oil chamber 135 through the pores 132.

  And as shown to Fig.9 (a), the hydraulic fluid of the 2nd oil path 42 is insufficient by leakage etc., pressure falls, and the valve body part 130 of the non-return valve body 122 receives from the charge oil path 43 side. When the pressure increases and this pressure becomes higher than the set pressure corresponding to the elastic force of the first spring member 126, the sliding body 142 moves upward against the elastic force of the first spring member 126; The valve body portion 130 is separated from the valve seat portion 121a of the valve seat 121 and is opened.

  Then, the hydraulic oil in the charge oil passage 43 flows from the outer spring chamber 143 through the gap between the valve body portion 130 and the valve seat portion 121a into the supply / exhaust port 129a and operates in the second oil passage 42. Oil is supplied.

  At this time, part of the hydraulic oil that has flowed into the inner spring chamber 134 flows into the oil chamber 135 through the pores 132, so that the hydraulic pressure of the hydraulic oil in the oil chamber 135 increases, and the sliding body The upward movement of 142 is promoted, and a larger amount of hydraulic oil can be supplied to the second oil passage 42.

  In this way, the second check relief valve 37 supplies hydraulic oil from the charge oil passage 43 to the second oil passage 42 in accordance with the differential pressure of the hydraulic oil between the charge oil passage 43 and the second oil passage 42. It can be replenished only on the side. In this case, the check valve body 122 operates as a pilot valve portion / main valve portion in the check valve.

  Conversely, as shown in FIG. 9B, the pressure of the hydraulic oil in the second oil passage 42 increases, and the pressure received by the valve body portion 139 of the relief valve body 127 from the second oil passage 42 side increases. When this pressure becomes higher than a set pressure corresponding to the elastic force of the second spring member 128, the relief valve body 127 moves downward against the elastic force of the second spring member 128, and the valve body portion thereof. 139 is separated from the valve seat 141 of the check valve body 122 and is opened.

  Then, the hydraulic oil in the second oil passage 42 passes through the gap 131 between the fine hole 131, the upper hole 136, the valve body part 139, and the valve seat part 141 in this order from the supply / discharge port 129a. 134 and further discharged through the flow holes 133 and 133 to the charge oil passage 43.

  At this time, the hydraulic oil that has flowed into the inner spring chamber 134 flows into the oil chamber 135 through the pores 132, and the hydraulic pressure of the hydraulic oil in the oil chamber 135 increases, as shown in FIG. As shown, the sliding body 142 moves upward. Then, the valve body part 130 of the check valve body 122 is separated from the valve seat part 121a, and a larger amount of the hydraulic oil in the second oil path 42 can be discharged to the charge oil path 43 through the gap therebetween. it can.

  Thus, when the pressure of the hydraulic oil in the second oil passage 42 becomes larger than a predetermined set pressure, the hydraulic oil can be discharged from the second oil passage 42 only to the charge oil passage 43 side. In this case, the relief valve body 127 operates as a pilot valve portion in the relief valve, and the check valve body 122 operates as a main valve portion in the relief valve.

  That is, the check relief valves 37 and 38 have a coaxial double structure in which the relief valve body 127 and the check valve body 122 are arranged inside and outside on the same axis, and therefore function as a check valve that prevents backflow of hydraulic oil. And check relief valves 37 and 38 having a function as a relief valve for discharging the hydraulic oil in order to make the pressure of the hydraulic oil in the first oil passage 41 and the second oil passage 42 which are the main oil passages lower than the set pressure. Can be configured integrally, and the number of parts can be reduced to further reduce the part cost.

  Further, in the check relief valves 37 and 38, the check valve body 122 is opened in conjunction with the opening of the relief valve body 127, and the first oil passage 41 or the first valve is opened via the check valve body 122. Since the relief structure that can discharge the hydraulic oil in the two oil passage 42 to the charge oil passage 43 is provided, the check relief valves 37 and 38 can function as so-called pilot-type relief valves, and a large amount of hydraulic oil is charged. Since the oil can be discharged to the oil passage 43, the relief performance can be improved.

  In addition, in the check relief valves 37 and 38, an oil chamber 135 is provided outside one end side of the sliding body 142, and the movement of the sliding body 142 is controlled by the pressure of hydraulic oil in the oil chamber 135, and Since the pore 132 is provided between the oil chamber 135 and the inner spring chamber 134 which is an oil chamber provided in the middle of the oil passage in the sliding body 142, the hydraulic oil in the inner spring chamber 134 By entering and exiting the oil chamber 135 via 132, it acts as a resistance against the movement of the sliding body 142, and can suppress the rapid movement of the check valve body 122 when the valve is opened or closed, increasing the relief flow rate. Unstable operation such as chattering at the time can be prevented.

Further, an alternative configuration of the check relief valves 36 and 37 will be described.
The hydraulic continuously variable transmission 1B shown in FIG. 15 is the same as the hydraulic continuously variable transmission 1 shown in FIG. 11 except that the check relief valves 36 and 37 of the charge circuit 52 are changed to check valves 144 and 145 and The plate angle control mechanism 53 is newly provided with a limiting circuit 146 for limiting the tilt angle of the first swash plate 10. Here, the description will focus on parts and configurations different from the hydraulic circuit of the hydraulic continuously variable transmission 1.

  In the charge circuit 147 of the hydraulic continuously variable transmission 1 </ b> B, a first check valve 144 is interposed between the charge oil passage 43 formed at the center of the input shaft 2 and the first oil passage 41. A second check valve 145 is interposed between the charge oil passage 43 and the second oil passage 42. Since the check valves 144 and 145 do not have a function as a relief valve, the check valves 144 and 145 can be made more compact than the check relief valves 36 and 37.

  The swash plate angle control mechanism 148 of the hydraulic continuously variable transmission 1B is provided with a 1-port 2-position pressure switching valve 149, and the pressure switching valve 149 is connected to the tilting actuator 54.

  The pressure switching valve 149 is provided with a reciprocally slidable spool 149 a, and an oil chamber 149 b with a spring member 159 provided on one end side of the spool 149 a is connected to the tilt actuator 54 via a pilot oil passage 150. It communicates with the front oil chamber 57. On the other hand, the oil chamber 149 c provided on the other end side of the spool 149 a communicates with the rear oil chamber 58 of the tilting actuator 54 via the pilot oil passage 151.

  Further, the pressure switching valve 149 is formed with a port 153 and a port 154, of which the port 153 communicates with an intermediate portion of the pilot oil passage 151 via the oil passage 152, while the port 154 The oil sump 156 communicates with the passage 155. The pressure switching valve 149 is normally set at the position 157 by the spring member 159.

  In the above-described configuration, the shift operation lever 76 is operated in the shift control in which the shift power output from the hydraulic continuously variable transmission 1B becomes high as the piston 55 slides forward. When the tilt changeover valve 61 is set to the position 74, the hydraulic oil flows from the servo oil passage 64 into the rear oil chamber 58, while the hydraulic oil is discharged from the front oil chamber 57 to the oil reservoir 71. Due to the differential pressure of the hydraulic oil in 57 and 58, the piston 55 slides forward, the first swash plate 10 tilts to the high speed side, and high speed transmission power is output.

  At this time, when the high speed transmission power receives a high load from the traveling wheels and the pressure of the hydraulic oil in the first oil passage 41 and the second oil passage 42 increases excessively, the forward sliding of the piston 55 is braked. Therefore, the pressure of the hydraulic oil in the rear oil chamber 58 is excessively increased by the hydraulic oil flowing from the servo oil passage 64.

  Then, this pressure acts on the oil chamber 149c via the pilot oil passage 151, the spool 149a is pushed forward against the elastic force of the spring member 159, and the setting of the pressure switching valve 149 is set at the position 157. To position 158.

  As a result, the hydraulic oil in the rear oil chamber 58 flows from the pilot oil passage 151 through the oil passage 152 to the port 153, flows out from the port 154 through the pressure switching valve 149, and then accumulates in the oil passage 155. It is discharged to 156.

  For this reason, the hydraulic oil in the rear side oil chamber 58 is restrained from excessively increasing its pressure, the piston 55 is prevented from sliding forward, or is slid backward. The pressure of the hydraulic oil in the first oil passage 41 and the second oil passage 42 does not increase any more.

  That is, in the tilting actuator 54 that changes the tilt angle of the first swash plate 10 of the hydraulic pump unit 5, when the piston 55 of the tilting actuator 54 is slid to the high speed side, the first oil path 41 and the second oil path 42. Since the tilt switching valve 61 capable of discharging the hydraulic oil from the rear oil chamber 58, which is a high-pressure side oil chamber that becomes a high pressure in conjunction with an increase in the pressure of the hydraulic oil inside, is provided, the first oil passage that is the main oil passage The function as a relief valve of the 41 / second oil passage 42 is not required, and the valve parts incorporated into the input shaft 2 can be made compact, and the assembly into the input shaft 2 is facilitated and the durability of the input shaft 2 is achieved. As a result, the assemblability and the device life of the hydraulic continuously variable transmission 1B can be improved.

Next, another embodiment of the tilting actuator 54 and the spool valves 20 and 31 will be described with reference to FIGS.
As shown in FIG. 13, in the tilting actuator 54, a universal joint 106 may be used for connection between the rod portion 55 b of the piston 55 and the locking portion 10 a of the first swash plate 10.

  The universal joint 106 is a ball type, and a first joint part 107 connected to the front end of the rod part 55b, and a spherical body 108a rotatably received in a receiver 107a of the first joint part 107. And a second joint portion 108 including

  A locking ring 108 b is formed at the front end of the second joint portion 108, and the locking portion 10 a is connected to the locking ring 108 b, and the locking portion 10 a and the piston 55 are connected to each other. Even if the relative posture changes due to misalignment or the like and a bending load is applied to the rod portion 55b, the load is dispersed by the universal joint 106.

  That is, since the universal joint 106 is used for the connection between the rod portion 55b of the piston 55 and the locking portion 10a from the first swash plate 10 in the tilt actuator 54, the rod portion 55b is bent due to misalignment or the like. It is possible to prevent the load from being applied, prevent the rod portion 55b from being damaged, and improve the life of the parts. Here, the universal joint 106 has been described with a ball type as an example, but a hook type may be used, and the type is not particularly limited.

  Further, as shown in FIG. 14, a swing mechanism 109 may be used for connection between the spool valves 20 and 31 and the cam grooves 34a and 35a of the spool cams 34 and 35. Since the structure of the swing mechanism 109 is substantially the same for the spool valves 20 and 31, the first spool valve 20 will be described here.

  The swing mechanism 109 is also a ball type like the universal joint 106 and has a guide shaft 114 protruding from the first spool valve 20 and a spherical shape rotatably received in a receiver 114a of the guide shaft 114. The swing member 115 includes a body 115a.

  A disc-shaped engaging portion 115b is formed at the rear end of the swing member 115, and the engaging portion 115b is engaged with the cam groove 34a of the first spool cam 34. Even when the cylinder block 4 that accommodates the spool valve 20 rotates, the swinging member 115 is moved along the cam groove 34a so that the engaging portion 115b is in surface contact with the groove surface of the cam groove 34a while swinging. be able to.

  That is, since the swing mechanism 109 is used for the connection between the spool valves 20 and 31 and the spool cams 34 and 35 that control the reciprocation of the spool valves 20 and 31, the engagement of the spool valves 20 and 31 is reduced. The joint portion 115b can be swung so that the engaging portion 115b and the cam groove 34a of the spool cams 34 and 35 can be brought into surface contact with each other. Can be improved.

  The present invention includes a hydraulic pump unit having a first plunger and a first swash plate with which the first plunger abuts, and a hydraulic motor unit having a second plunger and a second swash plate with which the second plunger abuts. Arranged before and after the input shaft in the axial direction across the cylinder block fitted to the input shaft, the cylinder block was provided with a pair of main oil passages communicating between the first plunger and the second plunger, It can be applied to all hydraulic continuously variable transmissions.

DESCRIPTION OF SYMBOLS 1 Hydraulic continuously variable transmission 2 Input shaft 4 Cylinder block 5 Hydraulic pump part 6 Hydraulic motor part 7 Housing 8 Swash plate holder 10 1st swash plate 10c Support shaft 12 1st plunger 22 2nd swash plate 24 2nd plunger 41 1st One oil passage (main oil passage)
42 Second oil passage (main oil passage)
48 Internal oil passage (primary oil passage)
49 Relief oil passage (secondary oil passage)
49a Inflow oil hole 49b / 49c Branch oil passage 50 / 50A Relief valve 51 Oil reservoir 52 Charge circuit 78 Through hole 78a Large diameter hole 78b Small diameter hole 80 Sleeve 80a Valve seat part 81 Valve body 82 Spring member 83a Discharge port 84 Large diameter part 85 Small-diameter portion 85b Inlet port 87 Valve body portion 88 First sliding portion 89 Second sliding portion 91 Primary pressure chamber 92 Secondary pressure chamber 93 Pore 94 Damper chamber 95 Spring chamber 98 Connection oil passage 99 Pressure receiving portion 102 Connecting oil Road (primary oil path)
103 Relief oil passage (secondary oil passage)

Claims (5)

  A hydraulic motor portion having a hydraulic pump portion having a first plunger and a first swash plate with which the first plunger abuts, and a second plunger and a second swash plate with which the second plunger abuts is applied to the input shaft. Hydraulic continuously variable transmission, which is arranged in front and rear in the axial direction of the input shaft across the fitted cylinder block, and is provided with a pair of main oil passages communicating between the first plunger and the second plunger in the cylinder block In the apparatus, the main oil passage is provided with a charge circuit, a relief valve is connected to the charge circuit, and a primary side oil passage from the charge circuit is communicated with the primary side oil passage from the charge circuit through an inlet port. A primary pressure chamber and a secondary pressure chamber communicating with the secondary oil passage to the oil reservoir via a discharge port; and the valve body of the relief valve is in contact with and separated from the valve seat portion of the sleeve. Primary pressure chamber and secondary pressure chamber A valve body part that connects and disconnects between the first body, a first sliding part that defines the primary pressure chamber between the valve body part and the one end side of the valve body; A second sliding portion defining a secondary pressure chamber between the valve body portion and the second sliding portion and the first sliding portion are slidably fitted into the sleeve. In addition, in the sleeve on the opposite side of the primary pressure chamber across the first sliding portion, a damper chamber communicating with the primary oil passage through the pore is provided, while the second sliding portion has A hydraulic continuously variable transmission comprising a pressure receiving portion for receiving the pressure of hydraulic oil flowing into the secondary pressure chamber from the primary pressure chamber.   A spring chamber is formed in the second sliding portion to house a spring member for urging the valve body in a valve closing direction in which the valve body portion is seated on the valve seat portion, 2. The hydraulic continuously variable transmission according to claim 1, wherein the hydraulic continuously variable transmission is used in at least a part of a communication oil passage from a pressure chamber to a discharge port.   The first swash plate is configured to be movable to form a movable swash plate, and the secondary oil passage is formed in a swash plate holder that supports the movable swash plate from the rear surface. 2. An inflow oil hole into which hydraulic oil from a discharge port flows, and a branch oil path that leads the hydraulic oil to flow down from the inflow oil hole to a predetermined position of the movable swash plate. The hydraulic continuously variable transmission according to claim 2.   The first swash plate is configured to be movable to be a movable swash plate, and a swash plate holder that supports the movable swash plate from the rear surface is further supported by a housing from the rear surface. While piercing through-holes composed of two-stage large-diameter holes and small-diameter holes, the sleeve has a large-diameter portion having the secondary pressure chamber therein, an outer diameter smaller than the large-diameter portion, and By forming a small-diameter portion having a primary pressure chamber in the front and rear, the relief valve can be inserted into the through-hole from the front side of the housing with the small-diameter portion first. The hydraulic continuously variable transmission according to claim 1 or 2.   The hydraulic continuously variable transmission according to any one of claims 1 to 4, wherein the primary oil passage and the secondary oil passage are arranged on the same axis of a relief valve. .

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