JP2530418Y2 - Swash plate pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to means for adjusting the tilt angle in a variable displacement swash plate pump. (Prior Art) A variable displacement swash plate pump is, for example, a swash plate. The swash plate is rotated in a direction perpendicular to the pump rotation axis by rotating an operation lever coupled to the pump to change the tilt angle, thereby changing the discharge amount per one rotation of the pump.

(Problem of the invention) In this case, the force required for the rotation operation of the operating lever is determined by the diameter of the pitch circle of the cylinder block accommodating the piston, the diameter of the piston, the load of the pump, the tilt angle of the swash plate, the tilt angle of the cylinder block. It is determined by the number of revolutions and the like, and when the operating conditions change, the force required to rotate the operation lever also changes. For this reason, when the operation lever is manually rotated via a link or the like, the operation force changes depending on operating conditions, and in some cases, an extremely large force is required.

The present invention has been made in order to solve the above problems, and a swash plate operating mechanism having a simple structure using a motor is incorporated into a pump so that the tilt angle can be adjusted with a constant small force. With the goal.

(Means for Achieving the Object) The present invention relates to a swash plate gear that rotates integrally with a swash plate in a swash plate pump provided with an operation lever for rotating and displacing the swash plate about a tilt axis. A drive gear that meshes with the gear,
A motor for rotating the drive gear, an arm for transmitting the rotation of the operation lever to the swash plate gear at a predetermined play interval, and a difference between the rotation angles of the operation lever and the swash plate gear within a range of the play interval is constant. And a switch for interrupting the energization when the power is below.

(Operation) When the operation lever is rotated, the switch is switched before the rotational power is transmitted to the swash plate gear via the arm, and the motor rotates to drive the swash plate gear through the drive gear and the swash plate gear meshing therewith. Rotate the plate. Further, when the rotation operation of the operation lever is stopped, the switch is turned off as the relative rotation position of the operation lever and the swash plate gear returns to the original position, the rotation of the motor stops, and the rotation of the swash plate also stops.

Further, in the event of a motor malfunction, the operating force is transmitted directly to the swash plate gear by rotating the operation lever beyond the range of play of the arm, and the swash plate can be driven without relying on the motor.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a pump housing of a hydraulic pump, 2 denotes a cylinder block which is rotatably supported by a rotation shaft 3 inside thereof, and 4 denotes a swash plate.

The cylinder block 3 includes a plurality of cylinders 6 formed in the axial direction. A base end of a piston 7 slidably projecting from each cylinder 6 is in sliding contact with the swash plate 4.

A valve plate 5 having a suction port and a discharge port communicating with each cylinder 6 is in sliding contact with the end of the cylinder block 2 on the side opposite to the swash plate 4, and these suction ports are fitted to a pump cover 19 that seals the pump housing 1. A suction passage and a discharge passage communicating with the port and the discharge port are formed.

Thus, when the rotating shaft 3 is driven to rotate, the cylinder 6
The piston 7 protruding from the swash plate 4 expands and contracts in accordance with the change in the distance between the swash plate 4 and the cylinder 6, and the hydraulic oil in the suction passage is sucked into the cylinder 6 from the suction port of the valve plate 5 in the extension stroke, and the hydraulic oil is contracted in the contraction stroke. Is pressurized and discharged to a discharge passage via a discharge port of the valve plate 5.

The swash plate 4 is supported by the pump housing 1 so as to be rotatable about a tilt axis 4A orthogonal to the rotation axis 3. Reference numeral 8 denotes a bearing for this purpose. Further, the swash plate 4 is formed integrally with a swash plate gear 9 having a tooth surface on the outer periphery on the tilt shaft 4A.

A motor 10 is mounted outside the pump housing 1. The rotating shaft 11 of the motor 10 projects freely inside the pump housing 1, and the driving gear 12 attached to the tip is engaged with the swash plate gear 9 as shown in FIG.

The shaft 13 faces the end face of the swash plate gear 9 and is supported by the pump housing 1 so as to be rotatable on the same axis as the swash plate gear 9.
The shaft 13 protrudes freely from the pump housing 1 to the outside, and an operating lever 14 is coupled to the protruding end. The operation lever 14 is manually rotated via a link 24 shown in FIG.

Further, an arm 15 is fixed to the shaft 13 in parallel with the end face of the swash plate gear 9, and stoppers 16 A and 16 B are provided between the arm 15 on the end face of the swash plate gear 9 in both rotation directions of the arm 15. Each is formed with a predetermined play interval.

Pistons 20A and 20B which are urged by a spring 17 and project toward the arm 15 are slidably housed in the stoppers 16A and 16B, respectively. Then, limit switches 21A and 21B which are pressed by the base ends of the pistons 20A and 20B and are turned ON are fixed to the end faces of the swash plate 9, respectively.

When the limit switch 21A is ON, the motor 10
The motor 10 is energized so as to rotate in the direction of the arrow in the figure, thereby rotating the swash plate gear 9 clockwise in the figure. When the limit switch 21B is ON, the motor 10 is energized so that the motor 10 rotates in the direction opposite to the arrow in the figure, thereby rotating the swash plate gear 9 counterclockwise.

Note that limit switches 21A and 21B are both pistons.
It stays ON only while it is pressed by 20A and 20B, and switches to OFF when released from the pressing force of pistons 20A and 20B.

Further, when the swash plate gear 9 rotates to a predetermined angle in the pump housing 14, a step 25 formed on the end face of the swash plate gear 9 is formed.
Limit switches 22A and 22B that come into contact with A and 25B, respectively, and cut off the current supply to the motor 10 are attached to target positions.

Also, a stepped portion of the swash plate gear 9 rotated at a predetermined rotation angle.
Protrusions 23A and 23B that abut against 25A and 25B, respectively, and that prevent further rotation of the swash plate gear 9 are fixed to the pump housing 1.

The rotation angle at which the swash plate gear 9 contacts the protrusions 23A and 23B is set to be slightly larger than the rotation angle at which the limit switches 22A and 22B are switched.

 Next, the operation will be described.

When no operating force is applied to the operating lever 14, the pistons 20A and 20B urged by the spring 17 act as δ _{1 in} FIG.
And δ ₂ are held at the neutral position where they are equal.

When it is desired to rotate the swash plate 4 clockwise in the drawing, the operation lever 14 is rotated in the same direction via the link 24 from this state. This resistance to rotation operation range of the angle [delta] ₁ biases the piston 20A toward the arm 15 the spring 17
The operating lever 14 rotates with a small operating force, and the arm 15 moves against the piston 17 against the spring 17.
Retreat A.

Then, when the base end of the retreating piston 20A presses the limit switch 21A and the limit switch 21A is turned on, the motor 10 rotates in the direction of the arrow in the drawing, and the drive gear 12
Then, the swash plate 4 is rotated clockwise in FIG. That is, the swash plate 4 starts to rotate in the same direction slightly after the rotation of the operation lever 14.

If the rotation of the operation lever 14 is continued with respect to the rotation of the swash plate 4, the limit switch 21A remains ON, so that the swash plate 4 also continues to rotate. During this time, the load applied to the operation lever 14 is only a constant repulsive force of the spring 17, so that a constant small operation force may be continuously applied to the operation lever 14.

Now, assuming that the target rotation angle of the swash plate 4 is α, the rotation of the operation lever 14 is stopped at a position where the operation lever 14 has rotated by the angle α. At the time of stop, since the arm 15 is still pressing the piston 20A, the limit switch 21A is ON, the motor 10 continues to rotate, and the swash plate gear 9 and the swash plate 4 also continue to rotate.

As a result, the stopper that rotates and displaces integrally with the swash plate gear 9
As the piston 16A moves away from the arm 15, the piston 21A biased by the spring 17 projects from the stopper 16A. Stops, and the rotation of the swash plate gear 9 and the swash plate 4 also stops.

That is, the rotation of the swash plate 4 is stopped slightly after the stop of the rotation operation of the operation lever 14. In this state, the arm 15 is held at the intermediate position between the stoppers 16A and 16B as before the start of the operation, and the swash plate 4 is held at the position rotated by the angle α.

The counterclockwise rotation of the swash plate 4 is performed similarly. That is, when the operation lever 14 is rotated counterclockwise and the limit switch 21B is turned ON via the piston 20B, the motor 10 rotates in the direction opposite to the arrow in the drawing, and the drive gear 12 and the swash plate gear 9 are rotated. The swash plate 4 is operated via the lever 14
The rotation starts slightly after the rotation operation. When the rotation of the operation lever 14 is stopped at the target angle β, the swash plate 4 also stops rotating at the same angle β as the rotation angle of the operation lever 14 with a slight delay.

In this manner, the swash plate 4 can be adjusted to an arbitrary tilt angle only by applying a constant small force to the operation lever 14.

By the way, when the rotation operation of the operation lever 14 is continued, the step 25A (25B) of the swash plate gear 9 comes into contact with the protrusion 23A (23B) fixed to the pump housing 1 and the further rotation of the swash plate 4 is continued. In this case, the step 25A (25B) comes into contact with the limit switch 22A (22B) before the rotation of the swash plate 4 is stopped, and the limit switch 22A (22B) is switched. Cut off the power supply to.

For this reason, there is no danger that the motor 10 will continue to be energized even after the rotation of the swash plate 4 is stopped, and the motor 10 will be heated.

If the motor 10 does not operate due to, for example, a trouble in the electric system, the operation of the operation lever 14 is continued so that the arm 15 is stopped according to the rotation direction.
The swash plate 4 can be directly rotated by the operation force of the operation lever 14 after contacting the swash plate 16A or 16B.

Although the hydraulic pump has been described in the above embodiment, a favorable effect such as a light shifting operation can be obtained also when the present invention is applied to a hydrostatic transmission, so-called HST.

(Effects of the Invention) As described above, the present invention includes the arm that transmits the rotation of the operation lever to the swash plate gear at a predetermined play interval, the motor that drives the swash plate gear to rotate, and the operation lever and the swash plate. The power supply to the motor is controlled via a switch that can be switched by the arm within the range of play with the gear, so when the operating lever is rotated, the operating lever directly switches the swash plate gear by switching the switch via the arm. The motor rotates the swash plate gear before driving, and when the rotation of the operation lever is stopped, the switch switches again due to the relative displacement between the arm and the rotating swash plate gear, and the motor stops rotating the swash plate gear. I do.

Therefore, the swash plate can be adjusted to an arbitrary tilt angle by continuously applying a constant small operation force to the operation lever,
The adjustment operation of the tilt angle becomes easy.

Also, even if the motor does not start due to a trouble in the electric system, the swash plate gear can be directly driven by the rotational force of the operation lever via the arm, and the tilt angle can be adjusted with human power. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a swash plate type hydraulic pump showing an embodiment of the present invention, and FIG. 2 is a view taken in the direction of arrow AA in FIG. 1 ... Pump housing, 4 ... Swash plate, 9 ... Swash plate gear, 10 ... Motor, 12 ... Drive gear, 13 ... Shaft, 14 ...
Operating lever, 15 Arm, 16A, 16B Stopper, 17
…… Spring, 20A, 20B …… Piston, 21A, 21B, 22A, 2
2B …… Limit switch.

Claims (1)

(57) [Scope of request for utility model registration] 1. A swash plate pump having an operation lever for rotating and displacing a swash plate about a tilt axis, a swash plate gear rotating integrally with the swash plate, a drive gear meshing with the swash plate gear, and
A motor for rotating the drive gear, an arm for transmitting the rotation of the operation lever to the swash plate gear at a predetermined play interval, and a difference between the rotation angles of the operation lever and the swash plate gear within a range of the play interval is constant. A switch for energizing the motor when the pressure exceeds the threshold, and for shutting off the power when the pressure falls below the threshold.