JP5978441B2 - Hydraulic continuously variable transmission - Google Patents

Description

  The present invention relates to a hydraulic continuously variable transmission in which a hydraulic pump and a hydraulic motor are arranged with respect to a cylinder block.

  Conventionally, HMT (Hydraulic Mechanical Transmission) or similar hydraulic continuously variable transmissions as disclosed in the following Patent Documents 1 to 3 have been provided. This hydraulic continuously variable transmission has a configuration in which a variable displacement hydraulic pump and a hydraulic motor are arranged with respect to a cylinder block. The hydraulic continuously variable transmission includes a hydraulic pump plunger fitted as one of the axial directions of the cylinder block in the axial direction of the cylinder block so as to be slidable back and forth within the cylinder block, and an end of the hydraulic pump plunger. A hydraulic pump swash plate that is in sliding contact with the hydraulic pump, and a hydraulic servo that changes the amount of inclination of the hydraulic pump swash plate. 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 A swash plate for a hydraulic motor is provided.

  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. By reciprocating the hydraulic motor plunger by the generated hydraulic pressure, the hydraulic motor swash plate pressed by the hydraulic motor plunger is rotated.

In the hydraulic continuously variable transmission as disclosed in Patent Documents 1 to 3, one of the hydraulic pump swash plate and the hydraulic motor swash plate is swingable and non-rotatable with respect to the input shaft. A swash plate body with which a plunger is slidably contacted with a cradle (hereinafter also referred to as “first cradle”) is supported. The other swash plate is configured such that the swash plate body is supported by a cradle (hereinafter also referred to as “second cradle”) that is not swingable and rotatable with respect to the input shaft.

JP 2008-185111 A JP 2012-66823 A JP 2006-275224 A

  Here, when the above-described hydraulic continuously variable transmission is mounted on a vehicle such as an automobile, the power transmission loss is minimized from the viewpoints of improving fuel consumption characteristics, suppressing weight increase, or suppressing manufacturing costs. It is desirable to make it possible to support each part with a low-cost and minimum number of bearings while restraining. However, in the hydraulic continuously variable transmissions disclosed in Patent Documents 1 and 2 above, the swash plate that is not swingable and rotatable with respect to the input shaft is supported using a tapered roller bearing and a needle roller bearing. Has been. Tapered roller bearings and needle bearings have a large power transmission loss and are expensive. Therefore, the above-described various problems cannot be solved by the hydraulic continuously variable transmission according to Patent Documents 1 and 2.

  Further, the hydraulic continuously variable transmission disclosed in Patent Document 3 discloses a configuration in which a swash plate that is not swingable and rotatable with respect to an input shaft is supported using a housing and a shaft. Yes. Specifically, in the hydraulic continuously variable transmission disclosed in Patent Document 3, the radial force is supported by two ball bearings provided between the housing and the shaft, and the thrust force is angular ball bearing. It is set as the structure supported by. In the case of adopting the configuration of Patent Document 3, the ball bearings are arranged on the outer diameter side of the swash plate and the outer diameter side of the cylinder block, which causes an increase in peripheral speed during driving and increases the transmission torque cross. Occurs. Further, in the structure of Patent Document 3, since at least three bearings are required, there is a problem that power transmission loss and weight increase correspondingly and fuel consumption characteristics deteriorate. In addition, the use of a large number of bearings also increases the manufacturing cost.

  Accordingly, an object of the present invention is to provide a hydraulic continuously variable transmission that is small and light in weight and low in manufacturing cost while minimizing power transmission loss.

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 transmission unit, an output shaft arranged along the input shaft and connected to the output side of the hydraulic continuously variable transmission unit so that power can be transmitted; the input shaft; the hydraulic continuously variable transmission unit; A cylinder block provided on a coaxial line so as to rotate integrally with an input shaft to which rotational power of the engine is input, and a housing for housing the output shaft. A plurality of plungers for a hydraulic pump inserted so as to be reciprocally slidable on a circumference around a coaxial line on one side in the axial direction, and a swash plate for a hydraulic pump slidably contacting the tip of the plunger for the hydraulic pump And the cylinder block On the other side in the axial direction of the hook, a plunger for a hydraulic motor inserted so as to be reciprocally slidable on the circumference around the coaxial line, and a tip for the hydraulic motor for sliding contact with the tip of the plunger for the hydraulic motor and a swash plate, wherein one of the swash plate and the swash plate of the hydraulic motor of the hydraulic pump, the relative pivotable and can not rotate the first cradle for one of the swash plate is the input shaft The hydraulic pump plunger is supported by a first swash plate body that is in sliding contact with the hydraulic pump plunger , and the hydraulic motor plunger is against the second cradle, the other of which is not swingable and rotatable with respect to the input shaft. A second swash plate body that is in sliding contact is supported, and the second cradle is rotatably supported with respect to the housing via an angular ball bearing, and is disposed between the input shaft and the second cradle. Niku Doru is rotatably supported through a ball bearing for supporting the ends of the second cradle side in said input shaft is supported by ball bearings for input shaft support relative to said housing, said angular The ball bearing and the ball bearing for supporting the input shaft are provided at positions overlapping in the direction intersecting the input shaft and the output shaft.

  In the hydraulic continuously variable transmission according to the present invention, the second cradle is rotatably supported with respect to the housing by the angular ball bearing and is also supported by the ball bearing disposed between the input shaft and the input shaft. It is supported so that it cannot swing and can rotate. In the present invention, the second cradle can be supported without using an expensive bearing with a large power transmission loss, such as a tapered roller bearing or a needle bearing. In addition, the number of bearings necessary for supporting the second cradle can be minimized. Therefore, according to the present invention, it is possible to provide a hydraulic continuously variable transmission that has a small power transmission loss, is small and lightweight, and is inexpensive to manufacture.

  In the hydraulic continuously variable transmission according to the present invention, a ball bearing for supporting the input shaft provided to support the end of the input shaft is attached to the housing. This ball bearing for supporting the input shaft has a positional relationship overlapping with the angular ball bearing provided for supporting the second cradle in the direction intersecting the input shaft and the output shaft (inter-axis direction). Is provided. As a result, the hydraulic continuously variable transmission can be made compact in the inter-axis direction.

  According to the present invention, it is possible to provide a hydraulic continuously variable transmission that is small and light in weight and low in manufacturing cost while minimizing power transmission loss.

It is sectional drawing which showed a part of drive train of the vehicle carrying the hydraulic continuously variable transmission which concerns on one Embodiment of this invention. 5 is a graph showing the relationship between the speed increasing ratio and the swash plate angle.

  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 a swash plate inclination adjusting mechanism 100. Etc. as main constituent members.

  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 X supplies the hydraulic motor M with the hydraulic pressure generated in the hydraulic pump P when the input shaft 20 and the cylinder block 30 rotate integrally, and causes the output unit 90 to output rotational power. 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. The rotational power of the engine (not shown) is transmitted to the input shaft 20 via the damper 12, the oil pump 14, and the like.

  The cylinder block 30 is integrally provided at an intermediate position of the input shaft 20. 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. Plural hydraulic pump plungers 40 are inserted on one side (engine side) of the cylinder block 30 so as to be slidable at equal intervals on a circumference around the axis. 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 100 described in detail later. Accordingly, the hydraulic pump swash plate 50 operates the swash plate inclination adjusting mechanism 100 to swing the pump cradle 52 about the swing center O located on the axis of the input shaft 20, thereby The amount of inclination of the plate 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). Plural hydraulic motor plungers 60 are inserted on the circumference around the axis of the input shaft 20 so as to be slidable at equal intervals. The hydraulic motor plunger 60 is biased toward the hydraulic motor swash plate 70 by a spring. The hydraulic pump swash plate 50 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. More specifically, the wall surface 16a of the transmission case 16 is provided with a cradle boss portion 16c into which the end portion of the motor cradle 72 can be inserted on the distal end side (downstream of power transmission) of the input shaft 20. . The motor cradle 72 is rotatably supported by an angular ball bearing 88 provided in the cradle boss portion 16c. The angular ball bearing 88 is installed at a position where it wraps (overlaps) in a direction intersecting the input shaft 20 and the output shaft 92 with respect to the ball bearing 22 provided for supporting the input shaft 20.

  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. As a result, the hydraulic motor M can function as a motor and output rotational power to the output unit 90. 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 unit 90 can be adjusted by operating the swash plate inclination adjusting mechanism 100 to change the inclination of the hydraulic pump swash plate 50.

  The output unit 90 is a part that outputs the rotational power generated by the action of the hydraulic pump P toward the differential gear 120 and the drive shaft 122 connected thereto. The output unit 90 is configured around an output shaft 92 (second axis) disposed substantially parallel to the input shaft 20. The output shaft 92 is rotatably supported via a ball bearing 93 provided in an output shaft boss portion 16 d formed on the wall surface 16 a of the transmission case 16. The ball bearing 93 is provided for the input shaft 20 and the output shaft 92 with respect to the angular ball bearing 88 provided for supporting the pump cradle 52 and the ball bearing 22 provided for supporting the input shaft 20. It is installed at a position that wraps (overlaps) in the intersecting direction. The output shaft 92 is provided with a wet friction clutch 95, a parking gear 97, and a parallel shaft gear 98 in this order in the axial direction.

  A second parallel shaft gear 96 is provided at one end of the output shaft 92 so as to be integrally rotatable. The second parallel shaft gear 96 meshes with a first parallel shaft gear 94 that is integrally provided on the outer periphery of the motor cradle 72. Therefore, the rotational power generated by the operation of the hydraulic pump P can be transmitted from the input shaft 20 to the output shaft 92 via both gears 94 and 96. A parallel shaft gear 98 is provided on the other end side of the output shaft 92. The parallel shaft gear 98 meshes with a parallel shaft gear 124 provided on the differential gear 120 side. Therefore, the rotational power transmitted from the hydraulic pump P to the output shaft 92 can be transmitted to the drive shaft 122 via the differential gear 120.

  As shown in FIG. 2, the hydraulic continuously variable transmission 10 outputs to the drive shaft 122 via the output unit 90 by adjusting the inclination of the hydraulic pump swash plate 50 using the swash plate inclination adjusting mechanism 100. In addition to adjusting the rotation speed (reduction ratio), the output rotation direction can be switched. Specifically, the swash plate inclination adjusting mechanism 100 includes a connection piece 102 connected to the pump cradle 52 of the hydraulic pump swash plate 50 and an actuator 104 connected to the connection piece 102. The swash plate inclination adjusting mechanism 100 can adjust the rotational speed by operating the actuator 104 to swing the motor cradle 72 and adjusting the amount of inclination. Furthermore, the rotation direction can be switched to the reverse side by inclining the motor cradle 72 further to the deceleration side than the angle at which the reduction ratio becomes infinite.

  Here, in the hydraulic continuously variable transmission 10, the actuator 104 is contracted, and the hydraulic pump swash plate 50 is inclined in the direction of arrow A in FIG. Rotating speed can be accelerated. On the contrary, by increasing the protrusion amount of the actuator 104 and inclining in the direction opposite to the arrow A (arrow B direction), the reduction ratio is increased and the rotational speed output to the output unit 90 is reduced. be able to. Further, when the hydraulic pump swash plate 50 is inclined by a predetermined angle in the deceleration direction (arrow B direction), the reduction ratio becomes infinite. When the angle of the hydraulic pump swash plate 50 when the reduction ratio becomes infinite is the boundary angle θ, the hydraulic pump swash plate 50 is further in the direction of arrow B (deceleration direction / increase direction of the reduction ratio) than the boundary angle θ. ), The rotation direction output to the output unit 90 can be reversed.

  As described above, in the hydraulic continuously variable transmission 10 according to the present embodiment, the motor cradle 72 is rotatably supported with respect to the transmission case 16 by the angular ball bearing 88 and between the input shaft 20 and the cradle 72. The ball bearing 80 is supported so as not to swing and to rotate with respect to the input shaft 20. By adopting such a configuration, the motor cradle 72 can be supported without using an expensive bearing with a large power transmission loss such as a tapered roller bearing or a needle bearing. Further, only two ball bearings 88 and 80 are required for supporting the motor cradle 72. Therefore, according to the above-described configuration, it is possible to make the hydraulic continuously variable transmission 10 small and light in weight and manufacturing cost while minimizing power transmission loss in the hydraulic continuously variable transmission 10. it can. Further, by reducing the weight of the hydraulic continuously variable transmission 10, it becomes possible to further improve the fuel consumption characteristics of a vehicle equipped with the hydraulic continuously variable transmission 10.

  The hydraulic continuously variable transmission 10 has a configuration in which the ball bearing 22 is attached to the outer peripheral side at the end on the motor cradle 72 side. As a result, the angular ball bearing 88 for supporting the cradle 72 for the motor and the ball bearing 22 for supporting the input shaft 20 are wrapped in the direction intersecting the input shaft 20 and the output shaft 92 (interaxial direction) ( Can be arranged to overlap). Therefore, the hydraulic continuously variable transmission 1 can be configured to be compact in the inter-axis direction.

  In the present embodiment, an example in which the inclination of the swash plate 50 for the hydraulic pump is made variable by the swash plate inclination adjustment mechanism 100 and the inclination of the swash plate 70 for the hydraulic motor is fixed is shown, but the present invention is limited to this. It is not something. That is, a configuration in which the inclination of the swash plate for hydraulic motor 70 can be changed by a mechanism corresponding to the swash plate inclination adjusting mechanism 100 instead of the swash plate for hydraulic pump 50, or the swash plate for hydraulic motor in addition to the swash plate for hydraulic pump 50 The plate 70 may have a variable inclination.

  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.

10 Hydraulic continuously variable transmission 16 Transmission case (housing)
20 Input shaft 22 Ball bearing 30 Cylinder block 40 Hydraulic pump plunger 50 Hydraulic pump swash plate 52 Pump cradle (first cradle)
54 Swash plate body for pump (first swash plate body)
60 Plunger for hydraulic motor 70 Swash plate for hydraulic motor 72 Cradle for motor (second cradle)
74 Swash plate body for motor (second swash plate body)
80 Ball bearing 88 Angular ball bearing 92 Output shaft

Claims (1)

An input shaft to which the rotational power of the engine is input;
A hydraulic continuously variable transmission portion connected to the input shaft so as to be capable of transmitting power;
An output shaft arranged along the input shaft, and connected to the output side of the hydraulic continuously variable transmission unit so as to be capable of transmitting power;
A housing that houses the input shaft, the hydraulic continuously variable transmission, and the output shaft;
The hydraulic continuously variable transmission is
A cylinder block provided on a coaxial line integrally with the input shaft to which the rotational power of the engine is input;
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,
Of the swash plate for the hydraulic pump and the swash plate for the hydraulic motor , the plunger for the hydraulic pump slides against the first cradle in which one of the swash plates is swingable with respect to the input shaft and cannot be rotated. A second swash plate body in which a first swash plate body in contact is supported, and the other swash plate body is in sliding contact with a second cradle that is not swingable and rotatable with respect to the input shaft. Is supported,
The second cradle is rotatably supported with respect to the housing via an angular ball bearing, and is also rotatably supported via a ball bearing for supporting the second cradle arranged between the input shaft. And
An end of the input shaft on the second cradle side is supported by a ball bearing for supporting the input shaft with respect to the housing,
The hydraulic continuously variable transmission, wherein the angular ball bearing and the ball bearing for supporting the input shaft are provided at positions overlapping in a direction intersecting the input shaft and the output shaft.

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