JP3554557B2 - Axial plunger pump and axial plunger motor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an axial plunger pump whose capacity can be changed without using a swash plate, and an axial plunger motor that can hold and discharge hydraulic oil in an oil chamber without using a rotary valve.
[0002]
[Prior art]
A continuously variable transmission combining a variable displacement axial plunger pump and a fixed displacement axial plunger motor is known.
[0003]
In a conventional axial plunger pump, the displacement is changed by changing the tilt angle of a swash plate that transmits the rotation of the input shaft to the pump plunger, thereby increasing or decreasing the stroke of the pump plunger. Further, in the conventional axial plunger motor, the holding and discharging of the hydraulic oil to and from the oil chamber that drives the axial plunger is performed by communicating and blocking an oil passage that opens on the sliding surface of the rotary valve.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is a first object of the present invention to provide a novel axial plunger pump capable of changing the stroke of a pump plunger without using a swash plate having a variable tilt angle. The present invention also provides an axial plunger pump that does not use a rotary valve. It is a second object of the present invention to provide a novel axial plunger motor capable of controlling the holding and discharging of hydraulic oil to and from an oil chamber for driving a plunger.
[0005]
[Means for Solving the Problems]
In order to achieve the first object, according to the invention described in claim 1, an input shaft, a plurality of pump cylinders arranged annularly so as to surround an axis of the input shaft, and each pump cylinder A pump plunger that is slidably fitted to the pump plunger, and an interlocking coupling unit that converts the rotation of the input shaft into a reciprocating motion of the pump plunger and changes a stroke of the reciprocating motion of the pump plunger. A drive gear provided on the input shaft, a driven gear provided on the pump plunger and meshing with the drive gear, and one end pivotally supported by the driven gear at a position eccentric from the axis of the pump plunger, and connected to the axis of the input shaft. An axial plunger pump is proposed, comprising a slider movable in the radial direction and a connecting rod pivotally supported at the other end.
[0006]
According to the above configuration, the interlocking connection means for interlockingly connecting the input shaft to the pump plunger includes a drive gear provided on the input shaft, a driven gear provided on the pump plunger and meshing with the drive gear, and an axis of the pump plunger. The driven shaft has one end pivotally supported by the driven gear at an eccentric position, and a connecting rod pivotally supported at the other end by a slider movable radially with respect to the axis of the input shaft. When the driven gear transmitted via the gear rotates, the connecting rod connecting the driven gear and the slider performs a precession motion to reciprocate a pump plunger integrated with the driven gear. At this time, by moving the slider pivotally supporting the other end of the connecting rod in the radial direction with respect to the axis of the input shaft, the reciprocating drive of the pump plunger can be performed without using the conventional tilting angle adjustable swash plate. Stroke can be changed.
[0007]
In order to achieve the second object, according to the invention described in claim 2, an output shaft, a plurality of motor cylinders arranged annularly so as to surround an axis of the output shaft, and each motor A motor plunger slidably fitted to the cylinder; a swash plate provided on the output shaft for converting reciprocating motion of the motor plunger into rotation of the output shaft; and holding of hydraulic oil in an oil chamber for driving the motor plunger. And a check valve for controlling the discharge, wherein the check valve separates the valve body from the valve seat, a valve seat formed inside the motor plunger, a valve body urged to be seated on the valve seat. And a projection which is provided integrally with the valve body for loosely penetrating the guide groove formed at the tip of the motor plunger and can contact the swash plate. Against the plunger axis, the axial piston motor is proposed which is characterized in that it is biased in the circumferential direction one side of the axis of the output shaft.
[0008]
According to the above configuration, the check valve for controlling the holding and discharging of the hydraulic oil in the oil chamber that drives the motor plunger has a valve seat formed inside the motor plunger, and a valve urged to be seated on the valve seat. A body and a projection provided integrally with the valve body and capable of loosely penetrating the guide groove formed at the tip of the motor plunger and abutting on the swash plate, with the apex of the projection relative to the axis of the motor plunger. In the suction stroke in which the motor plunger presses the swash plate, the apex of the projection is separated from the swash plate, so that the check valve is closed and the output shaft is displaced to one side in the circumferential direction of the axis of the output shaft. The swash plate pushes the top of the projection with the swash plate during the discharge stroke of the swash plate pushing the motor plunger to open the check valve and discharge the hydraulic oil. Since bets can, without using a conventional rotary valve, it is possible to control the retention and discharge of the working oil in the oil chamber that drives the motor plungers.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0010]
1 to 11 show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an axial plunger type continuously variable transmission, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 1. FIG. 4 is a sectional view taken along line 3-3, and FIG. 4 is a sectional view taken along line 4-4 in FIG. 5 is a sectional view taken along line 5-5 of FIG. 1, FIG. 6 is a sectional view taken along line 6-6 of FIG. 1, FIG. 7 is a sectional view taken along line 7-7 of FIG. FIG. 9 is an exploded perspective view of a motor plunger, FIG. 10 is an operation explanatory view of a check valve of an axial plunger motor, and FIG. 11 is an operation explanatory view corresponding to FIG.
[0011]
An axial plunger-type continuously variable transmission T in which a variable displacement axial plunger pump P and a fixed displacement axial plunger motor M are combined has a front housing 11 and a rear housing 12 divided into two in the direction of a first axis L1. The front and rear surfaces of a flange 13a protruding from the outer periphery of the cylinder block 13 housed inside the housings 11, 12, and a flange 11a protruding from the outer periphery of the front housing 11 and a flange protruding from the outer periphery of the rear housing 12. 12a are overlapped and fastened together with a plurality of bolts 16 via the sealing members 14 and 15. As a result, a first space 17 filled with hydraulic oil is defined between the front housing 11 and the cylinder block 13, and a second space 18 filled with hydraulic oil is defined between the rear housing 12 and the cylinder block 13. The first and second spaces 17 and 18 are separated from each other by a communication passage (not shown).
[0012]
Next, the structure of the variable displacement axial plunger pump P will be described with reference to FIGS.
[0013]
In the cylinder block 13, the pump cylinders 21 are formed on an odd number (five in this embodiment) of second axis lines L2 arranged at intervals of 72 ° about the first axis line L1. The pump plunger 23 is slidably and rotatably fitted through the seal member 22. An input shaft 26 is rotatably supported via ball bearings 24 and needle bearings 25 of the front housing 11 and the cylinder block 13, respectively, to close the first space 17 between the input shaft 26 and the front housing 11. Is disposed. A drive gear 28 is connected to an input shaft 26 between the ball bearing and the needle bearing 25 by a key 29, and the drive gear 28 meshes with a driven gear 30 formed integrally with the front end of each pump plunger 23.
[0014]
Five guide rails 31 are formed radially at an interval of 72 ° around the first axis L1 on the inner surface of the end of the front housing 11, and a slider 32 is slidably supported on each guide rail 31. The connecting rod 33 connecting the opposing pump plunger 23 and slider 32 has a first ball 33a and a second ball 33b at both left and right ends, respectively, and the first ball 33a engages with the slider 32 so as to swing freely. The second ball 33b swingably engages with the inner surface of the driven gear 30 at a position eccentric from the second axis L2 of the pump plunger 23.
[0015]
An operating rod 34 extending radially outward from each slider 32 penetrates the front housing 11 via a seal member 35, and the outer end of the operating rod 34 is bent forward by 90 °. An annular cam plate 36 is rotatably supported on the front surface of the front housing 11 via a guide member 37, and five cam grooves 36a formed on the cam plate 36 at an angle to the radial direction are provided in five cam grooves 36a. The tip of the operating rod 34 is slidably engaged. A convex portion 36b provided on the outer periphery of the cam plate 36 is connected to the actuator 38. When the actuator 38 is operated to rotate the cam plate 36, the operating rod 34 is guided to the cam groove 36a, thereby forming five Slider 32 moves inward and outward in the radial direction along the guide rail 31 at the same time.
[0016]
A check valve 41 is disposed inside the cylinder block 13 so as to be located on the second axis L2, and a first oil chamber 42 sandwiched between the pump plunger 23 and the check valve 41 is defined inside the pump cylinder 21. You. Inside each pump plunger 23, a check valve 46 that urges the valve body 44 toward the valve seat 45 by a spring 43 is housed, and the check valve 46 moves from the first space 17 to the first oil chamber 42. And the flow of hydraulic oil from the first oil chamber 42 to the first space 17 is regulated.
[0017]
Next, the structure of the check valve 41 will be described with reference to FIGS.
[0018]
The check valve 41 includes a valve housing 48 disposed on the second axis L2 and fixed by a clip 47. The valve body 51 is urged by a spring 50 toward a valve seat 49 formed in the valve housing 48. . Therefore, the check valve 41 allows the flow of the hydraulic oil from the first oil chamber 42 to the second oil chamber 52 described below, and regulates the flow of the hydraulic oil from the second oil chamber 52 to the first oil chamber 42. You.
[0019]
Next, the structure of the fixed displacement axial plunger motor M will be described with reference to FIG. 1 and FIGS.
[0020]
Motor cylinders 53 are formed on the five second axis lines L2 of the cylinder block 13, respectively. A motor plunger 54 is slidably and non-rotatably fitted to each motor cylinder 53 via a seal member 55. . In order to regulate the rotation of the motor plunger 54, the tip of a guide pin 56 projecting into the motor cylinder 53 engages with a guide groove 54a formed in the outer periphery in the axial direction.
[0021]
An output shaft 59 is rotatably supported by the rear housing 12 and the cylinder block 13 via a ball bearing 57 and a needle bearing 58, respectively, for closing the second space 18 between the output shaft 59 and the rear housing 12. Is disposed. A swash plate 61 having a fixed tilt angle is formed integrally with the output shaft 59, and the top surfaces of the five motor plungers 54 are formed in a conical shape corresponding to the tilt angle of the swash plate 61. Therefore, each motor plunger 54 comes into line contact with the swash plate 61 at the generating line of the conical top surface.
[0022]
Inside each motor plunger 54, a check valve 65 that urges the valve body 63 toward the valve seat 64 with a spring 62 is housed. The check valve 65 is moved from the second space 18 to the second oil chamber 52. And the flow of hydraulic oil from the second oil chamber 52 to the second space 18 is regulated.
[0023]
A claw-shaped protrusion 66 is formed integrally with the valve body 63 of the check valve 65, and the protrusion 66 loosely fits into a guide hole 54 b opened on the top surface of the motor plunger 54. The directions of the guide holes 54b of the motor plunger 54 are aligned in the circumferential direction around the first axis L1 (see FIG. 7). The tip of the projection 66 has an inclined surface 66a inclined with respect to the second axis L2, and a vertex 66b formed at the tip of the inclined surface 66a. The angle of the inclined surface 66a coincides with the cone angle of the top surface of the motor plunger 54, and the apex 66b of the projection 66 is biased in the circumferential direction with respect to the second axis L2.
[0024]
As shown by (1) and (3) in FIG. 10, when the motor plunger 54 is at the top dead center and the bottom dead center, the apex 66b of the projection 66 of the valve body 63 comes into contact with the swash plate 61. The position of the apex 66b of the projection 66 in the direction of the second axis L2 coincides with the tip of the conical apex of the motor plunger 54, and is set such that the surface pressure between the valve body 63 and the valve seat 64 becomes zero. .
[0025]
As shown by (2) in FIG. 10, when the motor plunger 54 drives the swash plate 61 while moving from the top dead center to the bottom dead center, that is, when the axial plunger motor M is in the suction stroke, the valve body Since the direction of the inclined surface 66a of the projection 66 of the projection 63 coincides with the inclination direction of the swash plate 61, when the inclined surface 66a is separated from the swash plate 61, the valve body 63 sits on the valve seat 64 and the check valve 65 is closed. It is maintained in a valve state.
[0026]
As shown by (4) in FIG. 10, when the motor plunger 54 is pushed back by the swash plate 61 and moves from bottom dead center toward top dead center, that is, when the axial plunger motor M is in the discharging stroke, the valve body Since the direction of the inclined surface 66a of the projection 66 of 63 and the direction of inclination of the swash plate 61 are opposite, the apex 66b of the projection 66 comes into contact with the swash plate 61, so that the valve body 63 separates from the valve seat 64. The check valve 65 is kept open.
[0027]
Therefore, when the swash plate rotates in the order of (1) → (2) → (3) → (4) → (1) ..., the check valve 65 is closed during the suction stroke between the top dead center and the bottom dead center. Then, the check valve 65 can be opened in the discharge stroke of the bottom dead center and the top dead center.
[0028]
Next, the operation of the embodiment of the present invention having the above configuration will be described.
[0029]
When the input shaft 26 rotates, five driven gears 30 meshing with a drive gear 28 provided on the input shaft 26 rotate together with the pump plunger 23 integrated therewith. The inner peripheral surface of each drive gear 30 and the corresponding slider 32 are connected by a connecting rod 33, and the position of the first ball 33a of the connecting rod 33 on the slider 32 side is set from the second axis L2 of the pump plunger 23. Because of the eccentricity, the second ball 33b performs precession about the first ball 33a. As a result, while the driven gear 30 makes one rotation, the pump plunger 23 makes one reciprocation between the bottom dead center position shown in FIG. 1 and the top dead center position shown in FIG. At this time, the stroke of the pump plunger 23 can be continuously adjusted from zero to a predetermined amount.
[0030]
That is, when the actuator 38 is driven to rotate the cam plate 36 about the first axis L, the five operating rods 34 engaged with the five cam grooves 36a move in the radial direction at the same time. The five sliders 32 connected to the rod 34 are guided by the guide rail 31 and move simultaneously in the radial direction. When the slider 32 moves inward in the radial direction and the first ball 33a moves on the second axis L2 of the pump plunger 23, the stroke of the pump plunger 23 becomes zero. Also, when the slider 32 moves radially outward to the position shown in FIGS. 1 and 11, that is, at a position where the connecting rod 33 can be parallel to the second axis L2 as the driven gear 30 rotates, the slider 32 is moved to the position shown in FIGS. When moved, the stroke of the pump plunger 23 is maximized.
[0031]
As shown in FIG. 3, the phases of the connecting rods 33 of the five pump plungers 23 are sequentially shifted by 72 ° with respect to the radial direction about the first axis L1, so that the five pump plungers 23 are at predetermined positions. Reciprocate sequentially with a time difference of. Then, when the pump plunger 23 advances from the bottom dead center toward the top dead center, the check valve 46 of the pump plunger 23 closes and the check valve 41 of the cylinder block 13 opens. Oil is pumped to the second oil chamber 52. As a result, the check valve 65 of the motor plunger 54 closes, the motor plunger 54 presses the swash plate 61, and the output shaft 59 integrated with the swash plate 61 rotates.
[0032]
As described above, during the suction stroke in which the motor plunger 54 presses the swash plate 61, the check valve 65 is maintained in the closed state by the action of the projection 66 provided on the valve body 63, and the motor plunger 54 moves the swash plate 61 Can be effectively pressed. When the five motor plungers 54 sequentially press the swash plate 61 with a predetermined time difference, the output shaft 59 rotates continuously.
[0033]
On the other hand, when the pump plunger 23 retreats from the top dead center to the bottom dead center, the check valve 41 of the cylinder block 13 is closed, but the check valve 46 of the pump plunger 23 is opened. The hydraulic oil passes through the check valve 46 and is sucked into the first oil chamber 42. When the motor plunger 54 is pushed back from the top dead center to the bottom dead center by the swash plate 61, the check valve 41 of the cylinder block 13 closes, but the check is performed by the action of the projection 66 provided on the valve body 63 as described above. The valve 65 is maintained in the open state, and the operating oil in the second oil chamber 52 can be discharged to the second space 18 through the gap between the guide hole 54b of the motor plunger 54 and the projection 66 of the valve body 63.
[0034]
If the cross-sectional area of the pump plunger 23 is the same as the cross-sectional area of the motor plunger 54, the stroke of the motor plunger 54 determined by the tilt angle of the swash plate 61 and the stroke of the pump plunger 23 determined by the radial position of the slider 32 , The rotation speed of the input shaft 26 and the rotation speed of the output shaft 59 match. If the stroke of the pump plunger 23 is reduced by changing the radial position of the slider 32 from this state, the capacity of the axial plunger pump P is reduced, while the capacity of the axial plunger motor M is constant. The rotation of the output shaft 59 is reduced with respect to the rotation of the shaft 26. Conversely, when the stroke of the pump plunger 23 is increased by changing the radial position of the slider 32, the capacity of the axial plunger pump P increases, while the capacity of the axial plunger motor M is constant. The rotation of the output shaft 59 is accelerated relative to the rotation of the shaft 26.
[0035]
In this way, by changing the position of the slider 32 with the actuator 38, the gear ratio of the axial plunger type continuously variable transmission T can be changed steplessly.
[0036]
Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made within the scope of the claims.
[0037]
For example, the valve body 63 of the check valve 65 does not need to have a ball shape, and an appropriate shape can be selected. Further, the shape of the projection 66 of the valve body 63 is not limited to the embodiment. The mechanism for driving the slider 32 is not limited to the embodiment.
[0038]
【The invention's effect】
As described above, according to the first aspect of the present invention, the interlocking connection means for interlockingly connecting the input shaft to the pump plunger meshes with the drive gear provided on the input shaft and the drive gear provided on the pump plunger. A driven gear, and a connecting rod pivotally supported at one end by the driven gear at a position eccentric from the axis of the pump plunger, and pivotally supported at the other end by a slider that is movable radially with respect to the axis of the input shaft. When the driven gear to which the rotation of the input shaft is transmitted via the drive gear rotates, the connecting rod connecting the driven gear and the slider performs a precession motion to reciprocally drive the pump plunger integrated with the driven gear. . At this time, by moving the slider pivotally supporting the other end of the connecting rod in the radial direction with respect to the axis of the input shaft, the reciprocating drive of the pump plunger can be performed without using the conventional tilting angle adjustable swash plate. Stroke can be changed.
[0039]
According to the second aspect of the present invention, the check valve for controlling the holding and discharging of the hydraulic oil in the oil chamber that drives the motor plunger is seated on the valve seat formed inside the motor plunger and the valve seat. A valve body that is biased as possible, and a projection that is provided integrally with the valve body and that can loosely penetrate the guide groove formed at the tip of the motor plunger and contact the swash plate. Since the motor plunger is deviated to one side in the circumferential direction of the axis of the output shaft with respect to the axis of the motor plunger, the top of the protrusion is separated from the swash plate during the suction stroke in which the motor plunger presses the swash plate. The check valve can be opened by pushing the top of the projection with the swash plate at the discharge stroke where the swash plate pushes the motor plunger. It is possible to discharge the hydraulic oil Te, without using a conventional rotary valve, it is possible to control the retention and discharge of the working oil in the oil chamber that drives the motor plungers.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an axial plunger type continuously variable transmission. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1. FIG. 3 is a sectional view taken along line 3-3 of FIG. 1. FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. 1. FIG. 6 is a sectional view taken along line 6-6 of FIG. 1. FIG. 7 is a sectional view taken along line 7-7 of FIG. FIG. 9 is an exploded perspective view of a motor plunger. FIG. 10 is an operation explanatory view of a check valve of an axial plunger motor. FIG. 11 is an operation explanatory view corresponding to FIG. 1 described above.
21 pump cylinder 23 pump plunger 26 input shaft 28 drive gear 30 driven gear 32 slider 33 connecting rod 52 second oil chamber (oil chamber)
53 Motor cylinder 54 Motor plunger 54b Guide hole 59 Output shaft 61 Swash plate 63 Valve body 64 Valve seat 65 Check valve 66 Projection 66b Apex L1 First axis (axis)
L2 2nd axis (axis)

Claims (2)

An input shaft (26), a plurality of pump cylinders (21) arranged annularly so as to surround an axis (L1) of the input shaft (26), and slidably fitted to each pump cylinder (21). A pump plunger (23) and interlocking coupling means for converting rotation of the input shaft (26) into reciprocating motion of the pump plunger (23) and changing a reciprocating stroke of the pump plunger (23);
The interlocking connection means,
A drive gear (28) provided on the input shaft (26);
A driven gear (30) provided on the pump plunger (23) and meshing with the drive gear (28);
One end is pivotally supported by the driven gear (30) at a position eccentric from the axis (L2) of the pump plunger (23), and is movable in the radial direction with respect to the axis (L1) of the input shaft (26). A connecting rod (33) pivotally supported at the other end by 32);
Axial plunger pump comprising: An output shaft (59), a plurality of motor cylinders (53) arranged annularly so as to surround an axis (L1) of the output shaft (59), and slidably fitted to each motor cylinder (53). A motor plunger (54), a swash plate (61) provided on the output shaft (59) for converting reciprocating motion of the motor plunger (54) into rotation of the output shaft (59), and a motor plunger (54). A check valve (65) for controlling retention and discharge of hydraulic oil in the oil chamber (52) to be driven;
The check valve (65) is
A valve seat (64) formed inside the motor plunger (54);
A valve body (63) urged to be seated on the valve seat (64);
The swash plate () is provided integrally with the valve body (63) so as to separate the valve body (63) from the valve seat (64), loosely penetrates a guide hole (54 b) formed at the tip of the motor plunger (54). 61) and a projection (66) that can be abutted on
The apex (66b) of the projection (66) is offset from the axis (L2) of the motor plunger (54) toward one circumferential side of the axis (L1) of the output shaft (59). Axial plunger motor.

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