JP6106833B2 - Hydraulic continuously variable transmission - Google Patents

Description

  The present invention relates to a hydraulic continuously variable transmission in which a cylinder block for a hydraulic pump and a cylinder block for a hydraulic motor are composed of one cylinder block.

  Conventionally, a hydraulic continuously variable transmission (HST) disclosed in Patent Documents 1 to 3 below is known as a type of continuously variable transmission.

  The hydrostatic continuously variable transmission disclosed in Patent Documents 1 and 2 includes a variable displacement type hydraulic pump and a hydraulic motor, and a cylinder block shared between the hydraulic pump and the hydraulic motor is provided between the hydraulic pump and the hydraulic motor. It is installed. On one side in the axial direction of the cylinder block, as a hydraulic pump component, a hydraulic pump plunger fitted in the cylinder block so as to be slidable in a reciprocating manner, and a hydraulic pump swash plate slidably contacting the end of the hydraulic pump plunger And a hydraulic servo for changing the inclination amount of the swash plate for the hydraulic pump. Also, on the other axial direction of the cylinder block, as a hydraulic motor component, a hydraulic motor plunger fitted in the cylinder block so as to be slidable back and forth, and a fixed inclination angle slidably contacting the end of the hydraulic motor plunger Swash plate for hydraulic motors.

  The cylinder block rotates integrally with the input shaft, and a hydraulic pump plunger fitted in the cylinder block is reciprocated by a hydraulic pump swash plate or the like inclined with respect to the axial direction to generate hydraulic pressure. The generated hydraulic pressure causes the hydraulic motor plunger to reciprocate, whereby rotational power is transmitted to the hydraulic motor swash plate pressed by the hydraulic motor plunger.

  The hydraulic continuously variable transmission disclosed in Patent Document 3 aims to ensure that the timing at which each spool slides is aligned and to allow each spool to slide smoothly and to prevent the occurrence of seizure. Is. In this hydraulic continuously variable transmission, each groove portion that engages one end of each timing spool is provided in each spool cam, and the contact portion of the groove portion with the engaging portion provided at the tip of each timing spool is viewed in cross section. It is set as the circular arc shape.

JP 2008-185111 A JP 2010-264809 A JP 2007-333209 A

  However, in the case of the configuration in which the engaging portion of the timing spool is engaged with the groove portion provided in the spool cam as in the hydraulic continuously variable transmission of Patent Document 3 described above, a large radial force or Surface pressure acts. Further, relative slip between the spool valve and the spool cam occurs. Therefore, in the case of the configuration as in Patent Document 3, there is a concern that the spool valve may be broken or burned.

  The present invention has been made in view of the above problems, and in a hydraulic continuously variable transmission in which a cylinder block for a hydraulic pump and a cylinder block for a hydraulic motor are constituted by one cylinder block, a spool valve and a sleeve are provided. It is an object of the present invention to provide a hydraulic continuously variable transmission capable of suppressing the seizure of a cylinder and the folding of a spool valve.

  The hydraulic continuously variable transmission of the present invention provided to solve the above-described problem includes an input shaft to which rotational power of an engine is input, and a hydraulic continuously variable transmission connected to the input shaft so that power can be transmitted. A cylinder block provided on the coaxial line so as to rotate integrally with the input shaft, and a circumference around the coaxial line in one axial direction of the cylinder block. On the other side in the axial direction of the cylinder block, a plurality of plungers for a hydraulic pump inserted so as to be reciprocally slidable at intervals, a swash plate for a hydraulic pump slidably contacting the tip of the plunger for the hydraulic pump, A plunger for a hydraulic motor inserted so as to be reciprocally slidable on a circumference around a coaxial line, and a swash plate for a hydraulic motor with which the tip of the plunger for the hydraulic motor is in sliding contact, Complete An oil passage through which pressure oil is supplied is provided inside the shaft, an oil chamber communicating with the oil passage, and a spool valve slidable in a direction along the input shaft inside the cylinder block. Is provided, and a curved portion curved so as to have a convex shape toward the outside is provided at the tip of the spool valve, and is in contact with the curved portion at a position adjacent to the tip side of the spool valve. A sleeve is provided, and the spool valve can be pushed and moved to abut against the sleeve by applying a hydraulic pressure of the oil chamber to a proximal end side of the spool valve; The surface in contact with the curved portion is characterized by having a shape that undulates in the direction of approaching and separating from the curved portion over the entire circumference of the sleeve.

  By adopting such a configuration, it is possible to suppress relative slip between the spool valve and the sleeve, and to suppress seizure of the tip portion of the spool valve and the sleeve. Moreover, according to this invention, the load which acts on the bending direction of a spool valve can be reduced, and it can suppress that a spool valve breaks.

  In the hydraulic continuously variable transmission of the present invention described above, the spool valve has a shaft-shaped valve body and a ball rotatably supported at an end of the valve body, and the curved portion is formed by the ball. It is desirable that is formed.

  By adopting such a configuration, it is possible to further reduce the relative slip between the spool valve and the sleeve and further suppress the seizure of the tip portion of the spool valve and the sleeve. Further, since the surface pressure acting between the valve body and the ball is small, seizure between the two hardly occurs.

  The hydraulic continuously variable transmission of the present invention described above is preferably provided with a through hole penetrating from the proximal end side to the distal end side of the spool valve.

  By adopting such a configuration, it becomes possible to supply the lubricating oil from the oil chamber provided on the proximal end side of the spool valve toward the distal end side. As a result, it is possible to further reduce the occurrence of seizure on the front end side of the spool valve.

  According to the present invention, in a hydraulic continuously variable transmission in which a cylinder block for a hydraulic pump and a cylinder block for a hydraulic motor are constituted by one cylinder block, the spool valve and the sleeve are seized and the spool valve is broken. Therefore, it is possible to provide a hydraulic continuously variable transmission capable of suppressing the above.

It is sectional drawing which shows the drive train of the vehicle carrying a hydraulic continuously variable transmission.

  Hereinafter, a hydraulic continuously variable transmission 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. The hydraulic continuously variable transmission 10 shown in FIG. 1 is a so-called HMT or the like. The hydraulic continuously variable transmission 10 includes an input shaft 20, a cylinder block 30, a hydraulic pump plunger 40, a hydraulic pump swash plate 50, a hydraulic motor plunger 60, a hydraulic motor swash plate 70, and the like as main components. I have.

  The hydraulic continuously variable transmission 10 includes a hydraulic continuously variable transmission X that is configured by disposing a variable displacement hydraulic pump P and a hydraulic motor M with respect to the cylinder block 30. The hydraulic continuously variable transmission section X can supply hydraulic pressure generated in the hydraulic pump P to the hydraulic motor M by the input shaft 20 and the cylinder block 30 rotating together, and output rotational power to the output side. It is possible. Hereinafter, the configuration of each part of the hydraulic continuously variable transmission 10 configured around the hydraulic continuously variable transmission part X will be described in more detail.

  The input shaft 20 is rotatably supported in the transmission case 16 via ball bearings 22 and 24. Specifically, the transmission case 16 has a wall surface 16a on the distal end side (downstream side of power transmission) of the input shaft 20. An input shaft boss portion 16b is provided at a position corresponding to the input shaft 20 on the wall surface 16a. The tip of the input shaft 20 is rotatably supported by a ball bearing 22 provided in the input shaft boss 16b. The base end side (upstream side of power transmission) of the input shaft 20 is rotatably supported by a ball bearing 24. Rotational power of an engine (not shown) is transmitted to the input shaft 20 via a damper (not shown), an oil pump 14 and the like.

  An oil passage 21 is formed in the input shaft 20 and pressure oil is supplied from the oil pump 14. The oil passage 21 has a main oil passage 21a formed so as to extend in the axial direction at a substantially axial position of the input shaft 20, and a sub oil passage 21b so as to branch in the radial direction in the middle of the main oil passage 21a. . The pressure oil supplied to the oil passage 21 is used not only for lubrication of each part and for replenishment of operating oil for the hydraulic continuously variable transmission 10 but also for cooling the cylinder block 30.

  The cylinder block 30 has a substantially columnar shape and is integrally provided at a midway position of the input shaft 20. The input shaft 20 is provided so as to pass through a substantially axial center position of the cylinder block 30. A hydraulic pump P is configured on one side (engine side) of the cylinder block 30 in the axial direction, and a hydraulic motor M is configured on the other side.

  Specifically, the main part of the hydraulic pump P is constituted by a hydraulic pump plunger 40 and a hydraulic pump swash plate 50 provided on one side of the cylinder block 30. The hydraulic pump plunger 40 can be slidably reciprocated on each of a plurality of pump plunger bores 42 provided on the one side (engine side) of the cylinder block 30 at equal intervals on the circumference around the axis. Has been inserted. The hydraulic pump plunger 40 is biased toward the hydraulic pump swash plate 50 by a spring. In the present embodiment, the hydraulic pump plunger 40 is an odd number of three or more.

  The main part of the hydraulic pump swash plate 50 is constituted by a pump cradle 52 (first cradle), a pump swash plate main body 54, and bearings 56 and 58. The hydraulic pump swash plate 50 is configured such that a pump swash plate main body 54 is attached to a pump cradle 52. Bearings 56 and 58 are interposed between the pump cradle 52 and the pump swash plate main body 54. Thus, the pump swash plate main body 54 is rotatably supported with respect to the pump cradle 52.

  The pump cradle 52 is supported so as not to rotate about the axis of the input shaft 20. The pump cradle 52 is connected to a swash plate inclination adjusting mechanism (not shown), and the pump scradle 52 is swung by operating the swash plate inclination adjusting mechanism to swing the pump cradle 52. The amount of inclination of the main body 54 with respect to the axis of the input shaft 20 can be arbitrarily adjusted.

  The hydraulic pump P activates the pump action when the cylinder block 30 and the hydraulic pump plunger 40 attached to the cylinder block 30 rotate about the axis along with the rotation of the input shaft 20. Specifically, the hydraulic pump plungers 40 are stroked between the cylinder block 30 and the pump swash plate body 54 while the cylinder block 30 makes a round around the axis of the input shaft 20 in conjunction with the input shaft 20. The possible length increases or decreases. Therefore, when the input shaft 20 rotates, the cylinder block 30 and the hydraulic pump plunger 40 attached to the cylinder block 30 rotate about the axis of the input shaft 20, and the hydraulic pump for sliding contact with the pump swash plate main body 54. The plunger 40 reciprocates, and the pump action is activated. The hydraulic pressure generated in the hydraulic pump P can be adjusted according to the amount of inclination of the hydraulic pump swash plate 50. The hydraulic pressure generated in the hydraulic pump P is supplied to the hydraulic motor M side (the hydraulic chamber in the cylinder block 30 that presses the base of the hydraulic motor plunger 60).

  The main part of the hydraulic motor M is constituted by a hydraulic motor plunger 60 and a hydraulic motor swash plate 70 provided on the other side in the axial direction of the cylinder block 30 (opposite the engine and the hydraulic pump P). The hydraulic motor plunger 60 is inserted into each of a plurality of motor plunger bores 62 provided at equal intervals on a circumference around the axis of the input shaft 20 so as to be reciprocally slidable. The hydraulic motor plunger 60 is biased toward the hydraulic motor swash plate 70 by a spring. The hydraulic pump plunger 40 and the hydraulic motor plunger 60 have different circumferential positions in the cylinder block 30. In the present embodiment, the hydraulic motor plunger 60 is an odd number of three or more.

  The main part of the swash plate for hydraulic motor 70 includes a motor cradle 72 (second cradle), a motor swash plate main body 74, and bearings 76 and 78. The hydraulic motor swash plate 70 is configured such that a motor swash plate main body 74 is attached to a motor cradle 72. Bearings 76 and 78 are interposed between the motor cradle 72 and the motor swash plate main body 74. Thus, the motor swash plate body 74 is supported so as to be rotatable with respect to the motor cradle 72.

  Unlike the above-described pump cradle 52, the motor cradle 72 cannot be adjusted in angle. Specifically, the motor cradle 72 is supported via a ball bearing 80 so as to be rotatable relative to the input shaft 20. The hydraulic motor swash plate 70 is rotatably supported in the transmission case 16 by an angular ball bearing 88 mounted on the outer peripheral side at the end of the motor cradle 72.

  The motor swash plate body 74 is attached to the motor cradle 72 described above. Therefore, unlike the swash plate main body 54 of the hydraulic pump swash plate 50 described above, the hydraulic motor swash plate 70 cannot change the amount of inclination of the motor swash plate main body 74. Further, the front end portion of the hydraulic motor plunger 60 is in sliding contact with the motor swash plate body 74.

  The hydraulic motor M exhibits its function as a motor when the cylinder block 30 and the hydraulic motor plunger 60 attached thereto rotate around the axis of the input shaft 20 as the input shaft 20 rotates. Specifically, the hydraulic motor plunger 60 reciprocates and slides with the pressure oil supplied from the hydraulic pump side, and while applying a thrust load to the hydraulic motor swash plate 70, the axis of the input shaft 20 together with the cylinder block 30. Rotate around. Thereby, the hydraulic motor M exhibits the function as a motor, and can output rotational power toward the output side. The rotational speed (reduction ratio) output from the hydraulic motor M changes according to the hydraulic pressure supplied from the hydraulic pump P described above. Therefore, the rotational speed (reduction ratio) output to the output side can be adjusted by operating a swash plate inclination adjusting mechanism (not shown) to change the inclination of the hydraulic pump swash plate 50.

  The above-described hydraulic oil inflow / outflow paths in the hydraulic pump P and the hydraulic motor M are switched by a pump spool valve 90 and a motor spool valve 92 provided in the cylinder block 30.

  The configurations of the pump spool valve 90 and the motor spool valve 92 will be described in more detail. The pump spool valve 90 and the motor spool valve 92 are respectively composed of shaft-shaped valve bodies 90a and 92a and curved portions 90b and 92b. Have The curved portions 90b and 92b are configured by attaching balls 90c and 92c so as to be freely rotatable at the tip portions of the valve bodies 90a and 92a, respectively. Further, through holes 90d and 92d penetrating from the proximal end side toward the distal end side are provided at substantially axial positions of the valve main bodies 90a and 92a.

  The pump spool valve 90 and the motor spool valve 92 are inserted into a pump valve housing portion 32 and a motor valve housing portion 34 provided in the cylinder block 30. The pump valve housing portion 32 and the motor valve housing portion 34 are provided at positions closer to the inner diameter side than the plunger bores 42 and 62 formed for the plungers 40 and 60 in the cylinder block 30. The pump valve accommodating portion 32 and the motor valve accommodating portion 34 are each formed in a direction along the input shaft 20. Therefore, the pump spool valve 90 and the motor spool valve 92 are slidable along the input shaft 20 in the pump valve housing portion 32 and the motor valve housing portion 34, respectively.

  The pump valve accommodating portions 32 and the motor valve accommodating portions 34 are alternately provided in the circumferential direction of the cylinder block 30. As shown in FIG. 1, the pump valve housing portion 32 is open on the hydraulic pump P side and is closed on the hydraulic motor M side. The motor valve housing 34 is open on the hydraulic motor M side and closed on the hydraulic pump P side. Oil chambers 36a and 36b are formed on the closed side of the pump valve accommodating portion 32 and the motor valve accommodating portion 34, that is, on the proximal end sides of the pump spool valve 90 and the motor spool valve 92, respectively. Pressure oil can be introduced into the oil chambers 36 a and 36 b via an oil passage 21 (a main oil passage 21 a and a sub oil passage 21 b) formed in the input shaft 20. Therefore, the pump spool valve 90 and the motor spool valve 92 can be pushed and operated from the proximal end side toward the distal end side by the hydraulic pressure of the oil chambers 36a and 36b from the input shaft 20 side.

  In addition, sleeves 91 and 93 are provided at positions adjacent to the leading end sides of the pump spool valve 90 and the motor spool valve 92. Thereby, the front-end | tip part of the spool valve 90 for pumps and the spool valve 92 for motors can contact | abut with respect to the sleeves 91 and 93, respectively. The sleeves 91 and 93 are respectively fixed to the hydraulic pump swash plate 50 and the hydraulic motor swash plate 70, and can swing or rotate together with the swash plates 50 and 70. Specifically, the sleeves 91 and 93 are fixed to the pump cradle 52 and the motor cradle 72, respectively.

  Further, in the sleeves 91 and 93, the contact surfaces 91a and 93a that contact the tip portions (curved portions 90b and 92b described in detail later) of the pump spool valve 90 and the motor spool valve 92 are respectively provided on the sleeves 91 and 93. The waveform has undulations corresponding to one cycle over the entire circumference. That is, the contact surfaces 91a and 93a have undulations in the directions approaching and separating from the curved portions 90b and 92b over the entire circumferences of the sleeves 91 and 93, respectively. When the sleeves 91 and 93 rotate once, the tip portions of the pump spool valve 90 and the motor spool valve 92 follow the contact surfaces 91 a and 93 a and reciprocate once in the direction along the input shaft 20.

  The pump spool valve 90 and the motor spool valve 92 perform valve operations for opening and closing the hydraulic oil flow path formed in the cylinder block 30 according to the rotational positions of the corresponding plungers 40 and 60, respectively. , 60 to switch the flow of the hydraulic oil that is sucked or discharged.

  The output of the hydraulic motor M described above is transmitted through a first parallel shaft gear 94 provided integrally on the outer periphery of the motor cradle 72 and a second parallel shaft gear 96 provided on one end side of the output shaft 100. It is transmitted to the output shaft 100. The power transmitted to the output shaft 100 is output toward a differential gear (not shown) and a drive shaft connected thereto.

  In the hydraulic continuously variable transmission 10 of the present embodiment described above, the curved portions 90b and 92b that are curved toward the outer side in the axial direction are provided at the tips of the pump spool valve 90 and the motor spool valve 92. It is provided and supported in a state where it abuts against the abutment surfaces 91a, 93a of the sleeves 91, 93. Further, the hydraulic pressures of the oil chambers 36a and 36b are applied to the proximal end sides of the pump spool valve 90 and the motor spool valve 92, thereby pushing and moving the pump spool valve 90 and the motor spool valve 92, and the sleeves 91 and 93. It is possible to make it contact | abut. Further, in the sleeves 91 and 93, the curved portions 90b and 92b and the contact surfaces 91a and 93a are in a direction in which the contact surfaces 91a and 93a of the sleeves 91 and 93 approach and separate from the curved portions 90b and 92b over the entire circumference. It has a corrugated shape with undulations. By adopting such a configuration, relative slip between the pump spool valve 90 and the motor spool valve 92 and the sleeves 91 and 93 is suppressed, and the leading end portion of the pump spool valve 90 and the motor spool valve 92 and the sleeve 91 are suppressed. , 93 can be suppressed. Further, the load acting in the bending direction of the pump spool valve 90 and the motor spool valve 92 can be reduced, and the pump spool valve 90 and the motor spool valve 92 can be prevented from being broken.

  Further, the hydraulic continuously variable transmission 10 has a curved portion 90b by balls 90c and 92c in which a pump spool valve 90 and a motor spool valve 92 are rotatably supported at the ends of shaft-shaped valve bodies 90a and 92a. , 92b are formed. As a result, the relative slip between the pump spool valve 90 and the motor spool valve 92 and the sleeves 91 and 93 is further reduced, and the leading end portions of the pump spool valve 90 and the motor spool valve 92 and the sleeves 91 and 93 are seized. Can be further suppressed. Further, the surface pressure acting between the valve main bodies 90a and 92a and the balls 90c and 92c is small, and seizure between the two hardly occurs.

  In the present embodiment, the example in which the curved portions 90b and 92b are configured by the balls 90c and 92c is shown, but the present invention is not limited to this. Specifically, the curved portions 90b and 92b may be formed by making the distal ends of the valve bodies 90a and 92a have a curved shape such as a substantially hemispherical shape.

  The hydraulic continuously variable transmission 10 has through holes 90d and 92d penetrating from the proximal end side to the distal end side of the pump spool valve 90 and the motor spool valve 92, and the pump spool valve 90 and the motor Lubricating oil can be supplied from the oil chambers 36a, 36b provided on the proximal end side of the spool valve 92 toward the distal end side. As a result, it is possible to more reliably prevent the seizure from occurring on the leading end sides of the pump spool valve 90 and the motor spool valve 92. In the present embodiment, the valve main bodies 90a and 92a are provided with the through holes 90d and 92d so that the hydraulic oil introduced into the oil chambers 36a and 36b can be used for lubrication. However, the present invention is not limited to this, and the through holes 90d and 92d may not be provided.

  INDUSTRIAL APPLICABILITY The present invention can be used as, for example, a hydraulic continuously variable transmission mounted on a vehicle such as an automobile, a motorcycle, a working vehicle such as a tractor, and particularly in a vehicle having a compact configuration such as a light vehicle. It can be suitably used.

DESCRIPTION OF SYMBOLS 10 Hydraulic type continuously variable transmission 20 Input shaft 21 Oil path 30 Cylinder block 38a, 38b Cooling oil flow path 40 Hydraulic pump plunger 50 Hydraulic pump swash plate 60 Hydraulic motor plunger 70 Hydraulic motor swash plate X Hydraulic stepless Speed change part

Claims (2)

An input shaft to which the rotational power of the engine is input;
A hydraulic continuously variable transmission connected to the input shaft so as to be capable of transmitting power;
The hydraulic continuously variable transmission is
A cylinder block provided on a coaxial line so as to rotate integrally with the input shaft;
Plural plungers for hydraulic pumps inserted in a reciprocating manner at intervals on a circumference around the coaxial line on one axial direction of the cylinder block;
A swash plate for a hydraulic pump that is in sliding contact with the tip of the plunger for the hydraulic pump;
On the other side in the axial direction of the cylinder block, a plunger for a hydraulic motor inserted so as to be reciprocally slidable on the circumference around the coaxial line; and
A swash plate for a hydraulic motor with which a tip of the plunger for the hydraulic motor is in sliding contact,
An oil passage for supplying pressure oil is provided inside the input shaft,
An oil chamber communicating with the oil passage and a spool valve slidable in a direction along the input shaft are provided inside the cylinder block.
A curved portion that is curved toward the outside toward the outside is provided at the tip of the spool valve,
A sleeve that is in contact with the curved portion is provided at a position adjacent to the distal end side of the spool valve,
It is possible to push and move the spool valve by causing the oil pressure of the oil chamber to act on the proximal end side of the spool valve, and to contact the sleeve,
The surface of the sleeve that comes into contact with the curved portion has a shape with undulations in the direction of approaching and separating from the curved portion over the entire circumference of the sleeve ,
The spool valve is
An axial valve body;
A ball rotatably supported at the end of the valve body,
The hydraulic continuously variable transmission, wherein the curved portion is formed by the ball. The hydraulic continuously variable transmission according to claim 1, wherein a through-hole penetrating from a proximal end side to a distal end side of the spool valve is provided.

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