JP2003065216A - Variable displacement swash plate type piston pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement swash plate type piston pump capable of preventing damage of a feedback mechanism part by a high frequency component of vibrational acceleration generated in a swash plate. SOLUTION: This variable displacement swash plate type piston pump is provided with a 2 degrees of freedom system feedback link 32 rotatably operating according to rocking of the swash plate 8, and operating sleeves 21 and 22 of a regulator 17 by moving a sleeve pin 31 in the Y 11 direction, a feedback groove member 12 integrally arranged in the swash plate 8, and transmitting the rocking of the swash plate 8, and a feedback pin 33 integrally arranged in the feedback link 32, and having a spherical projection 37 for engaging with the feedback groove member 12, and transmits the rocking of the swash plate 8 as a rotational movement of the feedback link 32. The feedback pin 33 includes a first divided part 35 composed of a springy elastic member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a construction machine such as a hydraulic excavator and is provided with a feedback link of a two-degree-of-freedom system which performs two operations of a rotating operation and an operation of moving in a predetermined direction. And a variable displacement swash plate type piston pump.

[0002]

2. Description of the Related Art A variable displacement type swash plate type piston pump provided with a feedback link of a two-degree-of-freedom system of this kind is described in, for example, Japanese Unexamined Patent Publication No. 10-205432.

FIG. 4 is a sectional view showing the structure of the main part of the conventional variable displacement type swash plate type piston pump shown in the above-mentioned publication, and FIG. 5 is a sectional view showing the regulator portion provided in the prior art shown in FIG. . These figures are described in the above-mentioned publication.

Further, FIGS. 6 to 8 are subscribed by the applicant of the present invention for the convenience of explaining the conventional technique shown in FIGS. 4 and 5, and FIG. 6 is a feedback link provided in the conventional technique shown in FIG. FIG. 7 is a perspective view showing a feedback pin portion, FIG. 7 is a view showing pump flow rate / discharge pressure characteristics set in a variable displacement type swash plate type piston pump, and FIG. 8 is a hydraulic circuit configuration in the vicinity of a regulator shown in FIG. It is a circuit diagram shown.

The conventional variable displacement type swash plate type piston pump shown in FIGS. 4 and 5 has a pump body 1 as shown in FIG.
, But is slidably housed in each of the rotary shaft 2, the cylinder block 4 that rotates integrally with the rotary shaft 2 and has a plurality of cylinders 3, and the cylinder 3 of the cylinder block 4, and the shoe 5 is attached to the tip thereof. The piston 6 and the swash plate 8 that is slidably supported by the concave curved surface 7 and is tiltably attached, and the shoe 5 of the piston 6 is in sliding contact with the piston 6, and controls the stroke of the piston 6. The tilt actuators 9 and 10 for controlling the tilt angle are provided.

Further, as shown in FIG. 5, a feedback transmission member which is provided integrally with the swash plate 8 and transmits the swing of the swash plate 8, that is, a feedback groove member 12 having a fitting groove 11, and this feedback groove member. A feedback pin 14 having a spherical projection 13 fitted in the fitting groove 11 of the end 12 at an end thereof, and a feedback link 16 to which the feedback pin 14 is integrally attached and rotatable around a support pin 15 is provided. ing.

Further, as shown in FIG. 5, a regulator 17 for controlling the tilt angle of the swash plate 8 through the tilt actuators 9 and 10 described above, thereby controlling the flow rate discharged from the pump, is provided. Spools 18 and 19 that constitute the flow rate adjusting valve, and sleeves 21 and 22 that are attached to the spools 18 and 19 and that are operated by the sleeve pin 20 provided on the feedback link 16 described above.
Is equipped with.

FIG. 6 shows a feedback link 16 having the above-mentioned support pin 15 and sleeve pin 20, and a feedback pin 14 provided integrally with the feedback link 16 and having a spherical projection 13.

The bottom side of the tilting actuator 10 for controlling the tilting angle of the swash plate 8 is, as shown in the circuit diagram of FIG.
And sleeve 21, and spool 19 and sleeve 2
2, the spool 18, the sleeve 21, and the spool 19 and the sleeve 22 are connected to a hydraulic pressure source 23.

In the prior art having such a configuration, as shown in FIG.
In order to prevent the engine stall at the time of pump overload, the horsepower control is performed so that the tilt angle of the swash plate 8 is set to the small tilt angle side to reduce the pump flow rate.

For example, when the pump flow rate is maximum when there is no load, that is, the tilt angle of the swash plate 8 is maximum, the discharge pressure of the pump rises as the actuator (not shown) is driven, and is shown in FIG. When the pump output horsepower curve 24 attempts to exceed the engine output horsepower curve 25, that is, when the pump output horsepower corresponding to the product PQ of the discharge pressure P and the pump flow rate Q attempts to exceed the engine output horsepower, FIG.
The discharge pressure P is given to the control unit 27 of the spool 18 via the oil passage 26 shown in (4), and the spool 18 is switched to the right position in FIG.

As a result, the pressure oil from the hydraulic power source 23 is passed through the spool 18 and the sleeve 21 to cause the tilt actuator 10 to move.
The tilt actuator 10 operates so as to reduce the tilt angle of the swash plate 8, that is, to swing the swash plate 8 in the direction of arrow 28 in FIG.

As the swash plate 8 swings in the direction of the arrow 28 in FIG. 8, the feedback groove member 12 swings integrally with the swash plate 8, and the feedback pin member moves in accordance with the swing of the feedback groove member 12. 14 moves in a predetermined direction orthogonal to the plane of FIG. 5 described above, that is, in the direction of arrow Y1 in FIG. Along with this, the feedback link 16 rotates around the support pin 15, and the sleeve pin 20 provided in the feedback link 16 moves in a predetermined one direction, that is, the arrow Y2 direction in FIG.

As a result, the sleeve 21 is moved to the arrow Y2 in FIG.
The tilt angle of the swash plate 8 is maintained so that the pump output horsepower moves within a range that does not exceed the engine output horsepower.

[0015]

When the variable displacement type swash plate type piston pump as described above is provided in a construction machine such as a hydraulic excavator, the swash plate 8 is caused by the discharge pressure pulsation at high pressure.
There is a tendency for high frequency components of excessive vibration acceleration to occur.

In such a situation, in the prior art shown in FIGS. 4 to 6, the feedback mechanism portion including the feedback groove member 12, the feedback pin 14, and the feedback link 16 is made of a rigid member. As described above, the high-frequency component of the vibration acceleration generated on the swash plate 8 acts on the feedback mechanism unit that connects the swash plate 8 and the regulator 17, which may damage the feedback mechanism unit, and There was a problem in terms.

The present invention has been made in view of the above-mentioned prior art, and an object thereof is a variable displacement swash plate type piston capable of preventing the feedback mechanism portion from being damaged by the high frequency component of the vibration acceleration generated in the swash plate. To provide a pump.

[0018]

In order to achieve the above object, the present invention rotates in response to the swing of a swash plate and moves in a predetermined direction to operate a sleeve provided in a regulator. A two-degree-of-freedom feedback link, a feedback transmission member integrally provided on the swash plate for transmitting the swing of the swash plate, and a feedback transmission member integrally provided on the feedback link and engaged with the feedback transmission member. A variable displacement swash plate type piston pump that transmits the swing of the swash plate as the rotation of the feedback link via the feedback transmission member and the feedback pin, the feedback transmission member, and At least one of the feedback pins is configured to include an elastic member having a spring property. .

According to the present invention thus constructed, at least one of the feedback transmission member integrally provided on the swash plate and the feedback pin integrally provided on the feedback link is used for the high frequency component of the vibration acceleration generated on the swash plate. Can be absorbed by the elasticity of the feedback mechanism, and thus damage to the feedback mechanism including the feedback transmission member, the feedback pin, and the feedback link can be prevented.

In the above invention, the feedback pin is detachably provided on the feedback link, and the second split is detachably provided on the first split portion and engages with the feedback transmission member. And the first divided portion may be made of the elastic member.

In this case, the first dividing portion may be constituted by a pipe-shaped member whose one side surface is open.

The second dividing portion may have a spherical projection, and the feedback transmission member may be a feedback groove member having a fitting groove into which the spherical projection is fitted.

Furthermore, in the above invention, the feedback pin is detachably provided on the feedback link, is made of the elastic member having a fitting groove, and the feedback transmission member is fitted in the fitting groove. The configuration may include a spherical protrusion.

Further, the feedback pin may be constituted by a pipe-shaped member whose one side surface is open.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a variable displacement swash plate type piston pump of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a feedback link and a feedback pin portion constituting a main part of one embodiment of the present invention, FIG. 2 is a view for explaining the feedback pin shown in FIG. 1, and FIG. Is a plan view showing a disassembled state, (b) is a sectional view taken along the line B of (a), (c)
6A is a C sectional view of FIG. 7A, and FIG. 8D is a D sectional view of FIG.

The variable displacement type swash plate type piston pump of this embodiment is provided in a construction machine such as a hydraulic excavator, and is different from the prior art shown in FIGS. 4 to 8 only in the feedback link and the feedback pin portion. The other components are shown in FIG.
This is equivalent to the conventional technique shown in FIG. Therefore, in the following, portions equivalent to those of the present embodiment will be described with reference to FIGS.
The description will be given using the reference numerals of the members shown in FIG.

As shown in FIGS. 1 and 2, in the present embodiment, the support pin 30 that forms the center of rotation and the sleeve pin 3 that operates the sleeves 21 and 22 illustrated in FIGS.
The feedback pin 33 is attachable to and detachable from the rigid feedback link 32 having the number 1.

That is, as shown in FIG. 2, the feedback pin 33 is detachably provided on the projecting portion 34 formed on the feedback link 32 and the detachable first split portion 35. The feedback dividing member provided integrally with the swash plate 8 described above, that is, the second dividing portion 3 engaging with the feedback groove member 12.
It consists of 6 and.

The first split portion 35 of the feedback pin 33
Is a pipe-shaped member formed of an elastic member having a spring property, for example, spring steel, and one side surface of which is open. The second split portion 36 is provided at its end with a spherical projection 37 that is fitted into the fitting groove 11 of the feedback groove member 12.

Also in this embodiment having such a configuration, the feedback groove member 12 is integrated with the swing of the swash plate 8 described above.
Oscillates, and the feedback pin 33 moves in the direction of the arrow Y11 in FIG. 1 with the oscillating of the feedback groove member 12. Along with this, the feedback link 32 rotates around the support pin 30, and the sleeve pin 31 provided in the feedback link 32 moves in a predetermined direction, that is, in the direction of arrow Y11 in FIG. With the movement of the sleeve pin 31, the sleeves 21 and 22 described above are
Moves, and the tilt angle of the swash plate 8 is controlled so that a predetermined pump flow rate is obtained.

When a high frequency component of the vibration acceleration is generated in the swash plate 8 due to the discharge pressure pulsation at high pressure, the first feedback pin 33 arranged in the transmission path connecting the swash plate 8 and the feedback link 32. Due to the elasticity of the divided portion 35, the high frequency component of the vibration acceleration is absorbed. Therefore, due to the high frequency component of this vibration acceleration,
Feedback link 32, feedback pin 33,
It is possible to prevent damage to the feedback mechanism portion including the feedback groove member 12, and ensure excellent durability.

FIG. 3 is a view showing a feedback pin portion constituting a main part of another embodiment of the present invention, (a) is a plan view showing a state in which the feedback pin is disassembled, and (b).
6A is a sectional view taken along the line B1 of FIG. 7A, FIG. 7C is a sectional view taken along the line C1 of FIG.

The variable displacement type swash plate type piston pump of this another embodiment is also provided in, for example, a hydraulic excavator, and is different from the prior art shown in FIGS.
Only the feedback link and feedback pin part. Therefore, also in the following, portions equivalent to those of the other embodiment will be described using the reference numerals of the members shown in FIGS.

Also in this alternative embodiment, the feedback pin 40 has the protrusion 3 formed on the feedback link 32.
It can be attached to and detached from 4. This feedback pin 4
0 is entirely made of an elastic member having a spring property, for example, a spring steel, and is made of a pipe-shaped member whose one side surface is open. Also, the feedback pin 40 is
A fitting groove 41 is provided at the end.

The feedback transmission member provided integrally with the swash plate 8 and transmitting the swing of the swash plate 8 has a spherical projection 42 fitted in the fitting groove 41 of the feedback pin 40 on the head, and has a spherical shape. Shaft part 4 that is continuously provided to the protrusion 42
3 comprises a member extending downward from the opening of the fitting groove 41 of the feedback pin 40.

The feedback link 32 is equivalent to that shown in FIG. 1, and is provided with a support pin 30 and a sleeve pin 31.

In another embodiment having such a configuration, the shaft portion 43 and the spherical projection 42, which constitute the feedback transmission member, swing integrally with the swing of the swash plate 8, and accordingly the spherical projection 42 and the spherical projection 42 move. The feedback pin 40 moves in the direction of the arrow Y3 in FIG. 3 through the relative rotation operation with the feedback pin 40. As a result, the feedback link 32 rotates, the sleeve pin 31 illustrated in FIG. 1 moves, the sleeves 21 and 22 move, and the tilt angle of the swash plate 8 is controlled so that a predetermined pump flow rate is achieved. .

Also in this other embodiment, when a high frequency component of the vibration acceleration is generated in the swash plate 8 due to the discharge pressure pulsation at a high pressure, the spring property of the feedback pin 33 causes the high frequency of the vibration acceleration. The components are absorbed, and the feedback mechanism such as the feedback link 32, the feedback pin 40, and the shaft portion 43 integrally provided with the spherical protrusion 42 can be prevented from being damaged, and excellent durability can be secured.

In each of the above-described embodiments, the first divided portion 35 of the feedback pin 33 or the entire feedback pin 40 is formed of an elastic member having a spring property. However, the feedback groove member 12 forming a feedback transmission member. Alternatively, the spherical protrusion 42, the shaft portion 43, and the like may be formed of an elastic member having a spring property.

In each of the above embodiments, spring steel is used as the elastic member having springiness, but synthetic resin or rubber may be used instead of spring steel.

[0042]

According to the inventions according to the respective claims of the present application, it is possible to prevent the feedback mechanism portion from being damaged by the high frequency component of the vibration acceleration generated in the swash plate, and to improve the durability as compared with the conventional one. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a feedback link and a feedback pin portion that constitute a main part of an embodiment of a variable displacement swash plate type piston pump of the present invention.

2A and 2B are views for explaining the feedback pin shown in FIG. 1, in which FIG. 2A is a plan view showing a state in which the feedback pin is disassembled, FIG. 2B is a sectional view taken along line B in FIG. 2A, and FIG. )
C sectional drawing of a figure, (d) is a D sectional view of a figure (a).

3A and 3B are views showing a feedback pin portion constituting a main part of another embodiment of the present invention, FIG. 3A is a plan view showing a state in which the feedback pin is disassembled, and FIG. 3B is a B1 in FIG. 3A. Sectional view, (c) is C1 sectional view of (a), (d)
FIG. 6D is a sectional view taken along line D1 of FIG.

FIG. 4 is a cross-sectional view showing a main part configuration of a conventional variable displacement swash plate type piston pump.

5 is a cross-sectional view showing a regulator portion provided in the conventional technique shown in FIG.

FIG. 6 is a perspective view showing a feedback link and a feedback pin portion provided in the conventional technique shown in FIG.

FIG. 7 is a diagram showing pump flow rate / discharge pressure characteristics set in a variable displacement swash plate type piston pump.

8 is a circuit diagram showing a hydraulic circuit configuration in the vicinity of a regulator in the conventional technique shown in FIG.

[Explanation of symbols]

1 Pump Main Body 8 Swash Plate 11 Fitting Groove 12 Feedback Groove Member (Feedback Transmission Member) 17 Regulator 18 Spool 19 Spool 21 Sleeve 22 Sleeve 30 Support Pin 31 Sleeve Pin 32 Feedback Link 33 Feedback Pin 34 Projection 35 First Dividing Part 36 Second split portion 37 Spherical protrusion 40 Feedback pin 41 Fitting groove 42 Spherical protrusion (feedback transmission member) 43 Shaft portion (feedback transmission member)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H070 AA01 BB04 BB06 CC07 DD05                       DD47 DD55                 3H075 AA02 BB03 CC18 DA03 DA04                       DB04 DB25

Claims (6)

[Claims] 1. A two-degree-of-freedom feedback link that rotates in response to rocking of the swash plate and moves in a predetermined direction to actuate a sleeve provided in the regulator, and is integrated with the swash plate. And a feedback pin that is integrally provided on the feedback link and that engages with the feedback transmission member. In a variable displacement swash plate type piston pump that transmits the rotation of the feedback link via the transmission member and the feedback pin, at least one of the feedback transmission member and the feedback pin includes an elastic member having a spring property. Variable displacement swash plate type piston pump characterized by. 2. The first division part, wherein the feedback pin is detachably provided on the feedback link,
The first split portion is detachably provided and is configured to include a second split portion that engages with the feedback transmission member, and the first split portion is configured of the elastic member. Variable displacement swash plate type piston pump. 3. The pipe-shaped member, wherein the first divided portion is open at one predetermined side surface.
Variable displacement swash plate type piston pump described. 4. The second division part has a spherical projection, and the feedback transmission member is a feedback groove member having a fitting groove into which the spherical projection is fitted. Variable displacement swash plate type piston pump. 5. The feedback pin is detachably provided on the feedback link, is made of the elastic member having a fitting groove, and the feedback transmission member includes a spherical protrusion fitted in the fitting groove. The variable displacement swash plate type piston pump according to claim 1. 6. The variable displacement swash plate type piston pump according to claim 5, wherein the feedback pin is formed of a pipe-shaped member whose one side surface is open.