JPH0614474U - Variable displacement pump / motor - Google Patents

Abstract

(57) [Abstract] [Purpose] Properly prevent the tilting moment to reduce energy loss during pintle operation. [Structure] Both sides 11a, 11b of the lining plate 11
Is provided with a taper angle α, and the source pressure P of the pump / motor is applied to both surfaces 11a and 11b thereof. And those faces 1
The resultant force of the vertical components of the hydraulic pressure urging forces F ₂ and F ₁ acting on 1a and 11b is exerted on the pintle 2 via the engaging piece 11c, and the upward movement of the pintle 2 due to the tilting moment M is prohibited.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable displacement pump / motor widely used in various hydraulic equipment fields.

[0002]

[Prior art]

 Examples of the variable displacement pump / motor whose volume changes due to the eccentric movement of the pintle include the radial piston type shown in FIGS. 4 and 5. As described in detail in Japanese Patent Application No. 56-175190, this case has a case 1 having an inverted trapezoidal inner surface 1a and an inverted trapezoidal shape which is disposed in the case 1 so as to be movable back and forth. A pintle 2 having a base end 2a fitted to the case inner surface 1a and a cone surface 2b formed at the upper end, a torque ring 3 rotatably arranged in the case 1, and a torque ring 3 inside the torque ring 3. A cylinder barrel 4 which is eccentrically and rotatably connected to the torque ring 3 and has an inner circumference 4a fitted and held on a cone surface 2b of the pintle 2, and an outer circumference of the cylinder barrel 4 in a radial direction at an equiangular position. A plurality of seal bushes 5 which are arranged so as to be capable of projecting and retracted and whose tip portions 5a are always in slidable contact with the inner circumference 3a of the torque ring 3, and the pintle 2 are urged so that the cylinder barrel 4 can be moved. Formed by and a pair of control pistons 6 to eccentric relative Kling 3.

The seal bushes 5 and the cylinder barrel 4 are surrounded by the protruding and retracting operation of each of the seal bushes 5 caused by the synchronous rotation of the cylinder barrel 4 and the torque ring 3 under eccentricity. The space S for inflowing and outflowing the fluid is expanded and contracted by the displacement volume according to the eccentricity d thereof, whereby the well-known operation as a pump / motor can be performed.

The case 1 and the pintle 2 are usually made of an aluminum alloy, and if the pintle 2 repeats the eccentric movement frequently, the inner surface 1a of the case 1 is easily worn. In order to prevent such an inconvenience, conventionally, a lining plate 7 whose both surfaces are parallel to each other is fixed to the case 1 side, and the pintle 2 is slidably contacted with the lining plate 7. Further, the space S is always connected to the fluid inflow / outflow ports 10a and 10b opening to the inner surface 1a of the case through the internal flow passages 2c and 2d formed in the pintle 2 and the hole 7a formed in the lining plate 7. The pressure fluid to be the original pressure is taken out from the high pressure side of either of the internal flow passages 2c and 2d through a shuttle valve (high pressure search valve) not shown, and then it is taken out from the cylinder chamber 6a of the control piston 6 or the shown chamber. Not supplied to the servo mechanism.

[0005]

[Problems to be solved by the device]

 By the way, suppose, for example, that the pump / motor works as a pump and discharges the pressure liquid from the space S to the fluid inflow / outflow port 10a through the internal flow path 2c and the hole 7a of the lining plate 7. The pressure in the space S is the discharge pressure (source pressure P), and the source pressure P is also introduced to the left control piston 6. In such a state, the direction and force point of the vector of force Fc for urging the pintle 2 by the control piston 6 and the direction and force point of force Fp for urging the pintle 2 by the hydraulic fluid in the space S. Is different from. Therefore, a tilting moment M as shown in the figure is generated on the pintle 2, and the tilting moment M easily tilts the pintle 2 to cause malfunction or inoperability during eccentricity. In order to prevent such a problem, conventionally, as shown in FIGS. 5 and 6, the base end portion 8a of the thin plate 8 is fixed to the pump / motor case 1 by the bolt 9 so that the leaf spring action is prevented. The front end portion 8b of the pintle 2 is brought into contact with the upper surface 2e of the pintle 2, and the pintle 2 is pressed downward by the spring force of the thin plate 2. The spring force is set to a value that balances the tilting moment M when the pump / motor source pressure P is maximized.

However, the pump / motor has a state in which the high pressure side and the low pressure side are both equal to each other, and the pressure P in the space S and the operating pressure P (charge pressure) of the control piston 6 are, for example, those of the pump itself. The minimum suction pressure is reached. Then, the tilting moment M also takes a small value. However, in the above-mentioned configuration, even in such a case, a strong spring force always acts on the pintle 2 from the thin plate 8 to cause a large frictional resistance between the pintle 2 and the lining plate 7 and between the pintle 2 and the thin plate 8. . Therefore, in order to operate the pintle 2 against such a resistance, it is necessary to introduce a pressure considerably higher than the above-mentioned minimum pressure into the control piston 6, and the energy loss of the entire system is large. There are challenges to be addressed.

An object of the present invention is to provide a pump / motor that effectively solves such problems with a simple structure.

[0008]

[Means for Solving the Problems]

 The present invention adopts the following configuration in order to achieve such an object.

That is, in the variable displacement pump / motor of the present invention, in which the pintle is slidably contacted with the inner surface of the case through the lining plate and the eccentric operation is performed along the inner surface of the case, the lining plate is provided. In addition to providing an engaging piece that prohibits the upward movement of the pintle, taper angles are applied to both sides of the lining plate, and the original pressure of the pump / motor is applied to these sides to apply hydraulic pressure to both sides. It is characterized in that the pintle is pressed downward through the lining plate by the resultant force of the urging force.

[0010]

[Action]

 With this configuration, when the pump / motor source pressure acts between the pintle and the lining plate and between the lining plate and the case, both surfaces of the lining plate form a taper angle, and these surfaces are The vertical component of the hydraulic urging force received is different, and the resultant force exerts a downward pressing force on the lining plate. Then, the force is also transmitted to the pintle via the engaging piece, and the pintle is also pressed downward. Since the pressing force is proportional to the source pressure, it is possible to prevent the tilting moment that occurs due to the source pressure with the same force and prevent the pintle from tilting.

By the way, in such a structure, when the source pressure is small, the pressing force to the pintle through the engaging piece also becomes small, and the frictional resistance between the pintle and the lining plate decreases. Therefore, even if the charge pressure introduced into the control piston is close to the suction minimum pressure of the pump itself, the pintle can be smoothly eccentrically operated.

[0012]

【Example】

 Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

This variable displacement pump / motor basically has a structure similar to that shown in FIGS. 5 and 6. Therefore, the common parts are denoted by the same reference numerals and the description thereof is omitted.

However, the pump / motor of this embodiment uses the lining plate 11 as shown in FIGS. 2 and 3. That is, in this lining plate 11, both surfaces 11a, 11b form a taper angle of angle α, and the surface 11a on the case 1 side is further inclined by an angle β with respect to the vertical direction. Further, the upper end of the lining plate 11 is expanded in a brim shape, and the right half region 11c of the lining plate 11 serves as an engaging piece of the present invention, and the engaging piece 11c abuts the upper surface 2e of the pintle 2. The upward movement of the pintle 2 when the tilting moment occurs is prohibited. An extension piece 11d on the left half is provided on the upper end of the case 1 so as to be temporarily temporarily fixed by a bolt 9. 11e is a hole for fluid inflow and outflow.

In such a configuration, for example, the pintle 2 is at the eccentric position shown in FIG. 5, and the pressurized liquid is discharged from the space S through the internal flow passage 2c and the hole 11e of the lining plate 11 into the fluid inflow / outflow port 10a. Assuming that this is the case, the pressure in the space S is the discharge pressure (source pressure P), and the source pressure P is also introduced to the left control piston 6. At this time, the pressurized liquid also circulates between the pintle 2 and the lining plate 11 and between the lining plate 11 and the case 1, and the original pressure P acts on each. Since both surfaces 11a and 11b of the lining plate 11 are tapered, the hydraulic biasing force F ₁ acts on the surface 11b on the pintle 2 side, and the vertical component F _1D is shown in FIG. As described above, F ₁ sin (α + β) is obtained, and the hydraulic pressure urging force F ₂ acts on the surface 11 a on the case 2 side, and the vertical component F _2D becomes F ₂ sin (β). Then, the resultant force F _1D −F _{2D of} the two vertical components F _1D and F _2D exerts a downward pressing force on the lining plate 11. Then, the force F _1D −F _2D is also transmitted to the pintle 2 via the engaging piece 11c, and the pintle 2 is also pressed downward. Since the pressing force F _1D −F _2D is proportional to the source pressure P, the tilting moment M, which is also generated according to the source pressure P and causes the upward movement of the pintle 2, is restrained with an appropriate force. The tilting of the pintle 2 can be prevented.

Moreover, in such a structure, when the source pressure P is small, the pressing force to the pintle 2 through the engaging piece 11c also becomes small, and the frictional resistance between the pintle 2 and the lining plate 11 decreases. . Therefore, even if the charge pressure introduced into the cylinder chamber 6a of the control piston 6 is lowered to the suction minimum pressure of the pump itself, the smooth behavior of the piston 2 can be ensured. It is possible to reduce the energy loss of the pump / motor and surely improve the efficiency of the entire system.

Although the bolts 9 for temporary fixing are fixed to the lining plate 11 in the above-mentioned embodiment, such bolts 9 are not always an essential requirement of the present invention. That is, only the engaging piece 11c may be provided on the upper end of the lining plate 11 and the extending piece 11d to the case 1 side may not be provided.

[0018]

As described above, the variable displacement pump / motor of the present invention is provided with a taper angle on both sides of the lining plate, and the source pressure of the pump / motor is applied to both sides of the lining plate. The resultant force of the vertical component of the pressing force is exerted on the pintle via the engaging piece, and the upward movement of the pintle due to the tilting moment is appropriately suppressed. For this reason, when the source pressure is low, the frictional resistance between the pintle and the lining plate decreases, and the smooth behavior of the pintle is ensured even if the charge pressure introduced to the control piston is lowered to near the suction minimum pressure of the pump itself. As a result, the energy loss of the pump / motor can be reduced as compared with the conventional one, and the effect of surely improving the efficiency of the entire system can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention, taken along a position crossing the center of a lining plate.

FIG. 2 is a view showing a lining plate of the same embodiment.

FIG. 3 is a right side view of FIG.

FIG. 4 is an operation explanatory view of the same embodiment.

5 is a partial cross-sectional view showing a conventional example, which is cut in a direction orthogonal to FIG.

FIG. 6 is a partial cross-sectional view corresponding to FIG. 1 of the conventional example.

[Explanation of symbols]

 1 ... Case 1a ... Inner surface 2 ... Pintle 11 ... Lining plate 11a, 11b ... Both sides 11c ... Engaging piece P ... Original pressure .alpha .... Taper angle

Claims (1)

[Scope of utility model registration request] 1. A variable displacement pump / motor in which a pintle is slidably contacted with an inner surface of a case via a lining plate and is eccentrically moved along the inner surface of the case. In addition to providing the prohibiting engagement piece, by applying a taper angle to both surfaces of the lining plate and applying the original pressure of the pump / motor to those surfaces, the lining plate is formed by the resultant force of the hydraulic pressure applied to both surfaces. A variable displacement pump / motor, characterized in that the pintle is pressed downward via the above.