JPH1162818A - Axial piston machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a radial load acting on bearings supporting the rotary shaft of an axial piston machine and to miniaturize the bearings. SOLUTION: An axial piston motor 25 of a hydromechanical transmission device for an automobile T is equipped with a rotary shaft 17 supported by three bearings, B4 to B6 , and a radial load, based on the driving force transferred by gears, 19 and 20, acts on the three bearings, B4 to B6 . As a radial load FS, based on a reactive force which a plunger 36 receives from a motor swash plate 38, acts on a motor cylinder 34 of the axial piston motor 25, the radial load acting on the three bearings, B4 to B6 , can be negated by the radial load FS based on the reactive force, by adjusting the direction of a trunnion shaft 39 of the motor swash plate 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an axial piston machine including an axial piston pump and an axial piston motor.

[0002]

2. Description of the Related Art A gear for transmitting a driving force is provided on a rotating shaft of such an axial piston machine, and a load applied from the gear to the rotating shaft causes a bearing for supporting the rotating shaft to a casing in a radial direction. Load acts. The radial load of the bearing fluctuates according to the output torque of the engine and the like, but it is necessary to determine the capacity of the bearing so that it can withstand the most severe operating condition in which the radial load becomes maximum.

[0003]

By the way, when the capacity of the bearing is increased, the size of the bearing is inevitably increased, and the layout in the casing becomes difficult. Therefore, the radial load acting on the bearing is reduced to reduce the bearing. It is desirable to reduce the size.

The present invention has been made in view of the above circumstances, and has as its object to reduce the radial load acting on a bearing that supports a rotating shaft of an axial piston machine, and to reduce the size of the bearing.

[0005]

Means for Solving the Problems In order to achieve the above object, the invention described in claim 1 comprises a rotating shaft rotatably supported by a casing via a plurality of bearings, and a rotating shaft supported by the rotating shaft. A plurality of cylinder holes formed so as to surround the rotation shaft, the cylinder opening at one axial end,
A plurality of plungers slidably fitted in the cylinder holes,
An axial piston machine comprising: a swash plate on which one end of a plunger abuts slidably; and a power transmission member provided on the rotary shaft for transmitting power between at least two members including the rotary shaft. The direction of the trunnion axis of the swash plate is set so that the radial reaction force received from the swash plate cancels the radial load acting on the bearing from the power transmission member via the rotating shaft.

According to the above structure, when the power transmission member transmits power, a radial load acts on the bearing supporting the rotary shaft provided with the power transmission member, while the reaction force received by the plunger from the swash plate is reduced. Since the power is transmitted to the rotary shaft via the cylinder, a radial load based on the reaction force acts on the bearing. At this time, by adjusting the direction of the trunnion shaft of the swash plate, the radial load acting on the bearing can be canceled by the radial load based on the reaction force from the swash plate, and the load on the bearing can be reduced to reduce the size. it can.

The bearing for supporting the rotating shaft need not be directly supported by the casing, but may be indirectly supported by the casing via another member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 5 show an embodiment of the present invention. FIG. 1 is an expanded skeleton diagram of a hydraulic and mechanical transmission for an automobile, and FIG. 2 is an enlarged view taken along a line 2-2 in FIG. , FIG. 3 is a perspective view showing a load acting on a power collecting shaft, FIG. 4 is a diagram for explaining a load acting on a bearing supporting a rotating shaft, and FIG. 5 is a relationship between a direction of a trunnion shaft and a load acting on the bearing. FIG.

In FIG. 1, T indicates a hydraulic / mechanical transmission for a front engine front drive type or rear engine rear drive type automobile. This hydraulic / mechanical transmission T comprises a mechanical transmission unit 1 and a hydrostatic continuously variable transmission 2.
, The engine E as a prime mover on one side,
The continuously variable transmission 2 is arranged on the other side.

The mechanical transmission unit 1 includes a power split device 3,
The mechanical transmission device 4, the power collective shaft 17, the reduction gear device 5, and the differential device 6 are housed in a common first casing 1c.

The power split device 3 is of a planetary gear type, and a torque damper 8 is mounted on a crankshaft 7 of an engine E.
Includes an input shaft 9 which connects via a first output shaft 10 ₁ arranged on the input shaft 9 and the coaxial line, and a second output shaft 10 ₂ surrounding the first output shaft 10 ₁ concentrically. On the input shaft 9,
A carrier 11 having a plurality of pinion shafts 12 on its outer periphery parallel thereto is fixed. Each of the pinion shafts 12 rotatably supports a pair of large and small pinion gears 13 and 14 integrally connected to each other. A small-diameter sun gear 15 meshing with the large-diameter pinion gear 13 is fixed to the first output shaft 10 _1. and large sun gear 16 which meshes with the small diameter pinion gear 14 is fixed to the second output shaft 10 _2.

The mechanical transmission 4 is provided with the second output shaft 10 _2.
, And a primary driven gear 19 fixed to the power collective shaft 17 and meshing with the primary drive gear 18. The power collective shaft 17 includes first and second output shafts 10 ₁ and 10 _2. And are arranged in parallel. The speed reducer 5 includes a final drive gear 20 fixed to the power collecting shaft 17 and a final drive gear 20 fixed to the differential case 22 of the differential device 6.
And a final driven gear 21 that meshes with.

The power gathering shaft 17 constitutes a rotating shaft of the present invention. The primary drive gear 18, primary driven gear 19, final drive gear 2
The zero driven gear 21 and the final driven gear 21 are both helical gears, and the primary driven gear 19 and the final drive gear 20 provided on the power collecting shaft 17 constitute a power transmission member of the present invention.

The differential device 6 is of a well-known type, and transmits the power transmitted from the final driven gear 21 to the differential case 22 to the left and right wheel drive shafts 23 supported by the differential case 22.
_L, is adapted to distribute the 23 _R, one of the continuously variable transmission 2 outer periphery thereof wheel drive shafts 23 _L, 23 _R, as in the illustrated example through its lower side differential device 6 power It is arranged parallel to the collective axis 17.

The continuously variable transmission 2 includes a hydraulic pump 24, a hydraulic motor 25, and a hydraulic closed circuit 26 for interconnecting these.
The control panel 27 is provided with a first casing 1 so as to be adjacent to the mechanical transmission unit 1.
c, and rotatably supports the first output shaft 10 ₁ and the power collecting shaft 17. Therefore, control panel 27 is arranged between mechanical transmission unit 1 and hydraulic pump 24 and hydraulic motor 25.

The hydraulic pump 24, hydraulic distribution surface of the control panel 27 while being connected coaxially to the first output shaft 10 ₁ 27
a pump cylinder 28 slidably disposed on a.
A large number of pump plungers 30 slidably supported by a large number of cylinder holes 29 in an annular arrangement provided around the axis of the pump cylinder 28, and are provided at the tip of each pump plunger 30 so as to swing freely. The pump swash plate 32 has a variable angle with which the shoe 31 slidably abuts, and is configured as a variable displacement type. That is, the pump swash plate 32 is disposed between the upright position orthogonal to the axis and the predetermined maximum tilt position inclined with respect to the coaxial line around the trunnion shaft 33 disposed orthogonal to the axis of the pump cylinder 28. Can be rotated. If the inclination angle α of the pump swash plate 32 from the upright position is increased, the reciprocating stroke of each pump plunger 30 can be increased.

On the other hand, a hydraulic motor 25 is coaxially connected to the power collecting shaft 17 and is rotatably slidably disposed on a hydraulic distribution surface 27a of a control panel 27; A large number of motor plungers 36 slidably fitted in a large number of cylinder holes 35 provided so as to surround the axis thereof, and a shoe 37 slidably provided at the tip of each motor plunger 36 is slidable. And a motor swash plate 38 which comes into contact with the motor, and is also configured as a variable displacement type. That is, the motor swash plate 38 has an upright position that intersects with the axis of the motor cylinder 34 around a trunnion shaft 39 that is disposed orthogonal to the axis of the motor cylinder 34, and a predetermined maximum inclination position that is inclined with respect to the coaxial line. The reciprocating stroke of each motor plunger 36 can be increased by increasing the inclination angle β of the motor swash plate 38 from the upright position.

The hydraulic pump 24 and the hydraulic motor 25
The second casing 2c for housing the control panel 27 and the first casing 2c
It is fixed to the casing 1c. And the first output shaft 10 ₁
The three bearings B _1, B _2, B ₃ through the first casing 1c, while being supported by the control board 27 and the second casing 2c, the power collecting shaft 17 three bearings B _4, B ₅ the first casing 1c via the B _6, is supported by the control board 27 and the second casing 2c.

FIG. 2 shows the power collecting shaft 1 toward the engine E.
7 when viewed in the axial direction of FIG.
The first output shaft 10 ₁ is arranged at the lower left of the vehicle, and the wheel drive shafts 23 _L and 23 _R are arranged at the lower right of the power collecting shaft 17. The primary driven gear 19 provided to the primary drive gear 18 and the power collecting shaft 17 provided on the second output shaft 10 ₂ and meshing point A, provided the power collecting shaft 17 final drive gear 20 and the wheel drive shaft 23L, 2
The final driven gear 21 arranged concentrically with the 3R meshes at a point B.

Referring to FIG. 3 together, it is apparent that
At the engagement point A, the primary driven gear 19 has
Tangential load FT from primary drive gear 18
_1, the radial loads FR _1, and the axial load FA ₁ acts. Further, at the meshing point B, the tangential load FT ₂ , the radial load FR _2, and the axial load FA are applied to the final drive gear 20 from the final driven gear 21.
₂ works. The axial loads FA ₁ and FA ₂ are applied to the primary drive gear 18 and the primary driven gear 1.
9. This occurs because the final drive gear 20 and the final driven gear 21 are helical gears.

As is apparent from FIGS. 1 and 3, when the motor swash plate 38 is inclined at an angle β with respect to the power gathering shaft 17, the shoes 37 of each motor plunger 36 slide on the sliding surface of the motor swash plate 38. To receive the reaction force in the direction perpendicular to
As the resultant force of the radial components, the motor plunger 36
A radial load FS acts on the power gathering shaft 17 from the motor cylinder 34 that slidably supports the power collecting shaft 17. The direction of the radial load FS is determined by the trunnion shaft 39 and the power collecting shaft 1.
7, and faces the motor plunger 36 at the bottom dead center.

Next, the operation of this embodiment will be described.

The power of the engine E is transmitted from the crankshaft 7 via the torque damper 8 to the input shaft 9 and thus the carrier 11.
Is supplied to the large and small pinion gears 13,
Divided by 14, the power transmitted to the large-diameter pinion gear 13 drives this by transmitted to the pump cylinder 28 via the first output shaft 10 ₁ from the small sun gear 15.

At this time, if the pump swash plate 32 and the motor swash plate 38 are each inclined at an appropriate angle from the upright position, the pump plunger 30 adjusts the inclination angle α of the pump swash plate 32 for one rotation of the pump cylinder 28. Since the discharge and suction operations are performed by reciprocating through the cylinder holes 29 with a corresponding stroke, the oil discharged from each of the cylinder holes 29 passes through the high pressure side of the hydraulic closed circuit 26 of the control panel 27 and the oil of the corresponding motor cylinder 34. When transmitted to the cylinder hole 35 to give an expansion action to the corresponding motor plunger 36, and the plunger 36 presses the motor swash plate 38, the rotation direction component of the reaction force rotates the motor cylinder 34 via the plunger 36. . After the expansion work, the motor plunger 36 is contracted by the motor swash plate 38, and the oil discharged from the corresponding cylinder hole 35 passes through the low pressure side of the hydraulic closed circuit 26, and the pump plunger 30 performs the suction operation. Is sucked into the cylinder hole 29. Thus, in the hydraulic motor 25, the motor plunger 36 reciprocates with a stroke corresponding to the inclination angle β of the motor swash plate 38, and the motor cylinder 34 makes one rotation for each reciprocation, and the torque is transmitted to the power collecting shaft 17. .

Thus, the respective capacities of the hydraulic pump 24 and the hydraulic motor 25 correspond to the corresponding plungers 30, 3 respectively.
6, which is determined by the angles α and β of the swash plates 32 and 38. The speed ratio of the continuously variable transmission 2 is stepless by changing the angles α and β of the swash plates 32 and 38. Can be controlled.

On the other hand, the motive power transmitted to the small diameter pinion gear 14, and transmitted from the large-diameter sun gear 16 to the second output shaft 10 _2, further mechanical transmission device 4, i.e. transmitted through the gears 18, 19 to the power collecting shaft 17 I do.

As described above, one of the powers of the engine E split by the power split device 3 is steplessly shifted by the hydrostatic type continuously variable transmission 2 and then reaches the power collecting shaft 17 while the other is driven. Since the power is efficiently transmitted by the mechanical transmission device 4 and reaches the power collecting shaft 17 as well, power transmission can be performed while satisfying both the performance of the continuously variable transmission and the transmission efficiency.

[0029] Then, the power and joined with the power collecting shaft 17 is transmitted to the differential device 6 through the reduction gear 5 are distributed here to the left and right wheel drive shaft 23 _L, 23 _R.

By the way, as shown in FIG.
The bearings Ba and Bb separated by L separate the ends of the rotating shaft S from each other.
Supported, and a radial load F is applied to a gear G provided on the rotation shaft S.
When R is added, the point of application of the radial load FR
Distance L from bearing Ba ₁Just be away, bear
From the balance of the moment around the ring Bb, FR * (LL₁) = Fa * L holds, and from this equation, the load acting on the bearing Ba
Fa is expressed as follows: Fa = ｛(L−L₁) / L｝ * FR.

From the balance of the moment around the bearing Ba, FR * L ₁ = Fb * L is established. From this equation, the load Fb acting on the bearing Bb is given by Fb = (L ₁ / L) * FR.

Further, as shown in FIG. 4B, both ends of the rotating shaft S are supported by bearings Ba and Bb separated by a distance L, and a pitch circle of a gear G having a pitch circle radius r provided on the rotating shaft S is provided. When an axial load FA is applied to the circumference, FA * r = Fa * L is established from the balance of the moment around the bearing Bb. From this equation, the load Fa acting on the bearing Ba is expressed as: Fa = (r / L) * FA Given by

From the balance of the moment around the bearing Ba, FA * r = -Fb * L is established. From this equation, the load Fb acting on the bearing Bb is given by Fb =-(r / L) * FA.

As is apparent from FIG.
, Three radial loads FR ₁ , FR ₂ , FS and two axial loads FA ₁ , FA ₂ are applied. As a superposition of these five loads, each of the bearings B ₄ -B
The magnitude of the radial load acting on ₆ can be calculated. However, the power collective shaft 17 has three bearings B ₄ to
For supported by B _6, a so-called non-static Teihari, actual analysis is complicated as compared with that of FIG.

FIG. 5 is a graph obtained by analyzing the magnitude of the radial load acting on the three bearings B _{4 to} B ₆ of the power collecting shaft 17 by using a computer. The horizontal axis indicates the motor swash plate of the hydraulic motor 25. 38 shows the direction θ of the trunnion shaft 39 (specifically, the direction of the reaction force FS that changes according to the direction of the trunnion shaft 39 shown in FIGS. 2 and 3), and the vertical axis represents the three bearings. It shows the radial loads acting on B _{4 to} B ₆ and the total value of the three radial loads. When the direction θ of the trunnion shaft 39 changes, 3
Although the magnitude of the radial load acting on each of the bearings B _{4 to} B ₆ also changes, it can be seen that when θ = 190 °, the total value of the three radial loads becomes a minimum of 6,800 kgf. At this time, the loads on the bearings B ₄ and B ₅ are 3400 kgf and 1000 kgf, respectively, and the dispersion is large. When the direction θ of the trunnion shaft 39 is set to 130 °, the total value of the radial loads slightly increases. And the radial load of
It can be suppressed to 600 kgf or less.

As described above, by appropriately setting the direction θ of the trunnion shaft 39 of the motor swash plate 38, the primary driven gear 19 and the final drive gear 20
From a radial load that is input to the three bearing B ₄ .about.B _6, canceled by radial load FS based on the reaction force from the motor swash plate 38, downsized to reduce the load of the bearing B ₄ .about.B ₆ Can be planned.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the present invention is applied to a hydraulic motor 2
5, the present invention can be applied to the hydraulic pump 24. Also, the power collecting shaft 17
Not only is the load transmitted through the primary driven gear 19 and the final drive gear 20 but also the load due to the weight of the motor cylinder 34 and the like acts on the trunnion shaft of the motor swash plate 38 in consideration of the load due to this weight. If the direction of 39 is determined, the load acting on the bearings B _{4 to} B ₆ can be reduced more effectively.

[0039]

As described above, according to the first aspect of the present invention, when the power transmission member transmits power, a radial load acts on the bearing that supports the rotating shaft provided with the power transmission member. On the other hand, since the reaction force received by the plunger from the swash plate is transmitted to the rotary shaft via the cylinder, a radial load based on the reaction force acts on the bearing. At this time, by adjusting the direction of the trunnion shaft of the swash plate, the radial load acting on the bearing can be canceled by the radial load based on the reaction force from the swash plate, and the load on the bearing can be reduced to reduce the size. it can.

[Brief description of the drawings]

FIG. 1 is an expanded skeleton diagram of a hydraulic and mechanical transmission for an automobile.

FIG. 2 is an enlarged view taken on line 2-2 of FIG. 1;

FIG. 3 is a perspective view showing a load acting on a power collecting shaft.

FIG. 4 is a diagram illustrating a load acting on a bearing that supports a rotating shaft.

FIG. 5 is a graph showing the relationship between the direction of the trunnion shaft and the load acting on the bearing.

[Explanation of symbols]

1c First casing (casing) 2c Second casing (casing) 17 Power gathering shaft (rotating shaft) 19 Primary driven gear (power transmission member) 20 Final drive gear (power transmission member) 34 Motor cylinder (cylinder) 35 Cylinder hole 36 Motor Plunger (plunger) 38 Motor swash plate (swash plate) 39 Trunnion shaft B ₄ bearing B ₅ bearing B ₆ bearing

Claims (1)

[Claims] 1. A casing (1c, 2c) and a plurality of bearings _{(B 4, B 5, B} 6) rotatably through a supported rotating shaft (17), is supported by a rotating shaft (17) A cylinder (34) having a plurality of cylinder holes (35) formed to surround the rotation shaft (17) and open at one axial end, and a plurality of cylinders (35) slidably fitted in the cylinder holes (35). A plunger (36), a swash plate (38) with which one end of the plunger (36) slidably abuts, and a rotary shaft (17) for transmitting power between at least two members including a rotary shaft (17). ) Provided in the axial piston machine, the radial reaction force received by the plunger (36) from the swash plate (38) by the power transmission member (19, 20). From the shaft via the rotary shaft (17) Grayed _{(B 4, B 5, B} 6) so as to cancel the radial load acting on an axial piston machine, characterized in that setting the direction of the trunnion axis (39) of said swash plate (38).