JP2003343421A - Swash plate type fluid machine provided with swash plate pressure equalization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swash plate type fluid machine improved in durability by avoiding local increase of bearing pressure of a swash plate slide surface at a position close to a high-pressure fluid passage, and by improving the smoothness of the swash plate slide surface to prevent occurrence of wear or seizure on the swash plate slide surface. <P>SOLUTION: This swash plate type fluid machine is provided with a swash plate slidably supported by a case member on the slide surface formed on a back part, and is so structured as to make the swash plate slide surface receive pressure acting on a piston by a working fluid flowing in a high-pressure side fluid passage or in a low-pressure side fluid passage. The fluid machine is characterized by forming a plurality of pressurized fluid grooves in a position, of the slide surface of the swash plate, closer to the high-pressure fluid passage than a rotation axis in a projection surface in the direction of the rotation axis, and by being provided with a pressurized fluid passage for feeding a pressurized fluid to the pressurized fluid grooves. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a swash plate hydraulic pump or hydraulic pump, a swash plate hydraulic motor, a hydraulic motor, or the like, and is intermittently applied to a piston that reciprocates in a cylinder rotatable relative to the swash plate. A swash plate type having a swash plate equalizer configured to receive the pressure acting on the piston by the working fluid flowing in the high pressure fluid passage or the low pressure fluid passage communicated with the swash plate. Related to fluid machinery.

[0002]

2. Description of the Related Art A swash plate type hydraulic pump is often used for hydraulic machines such as hydraulic drive units for construction machines and steering gears for ships. In such a swash plate type hydraulic pump, an inclination angle (swash plate angle) can be adjusted, and a swash plate slidably supported by a case member by a semi-cylindrical sliding surface formed on the back is provided. The pistons fitted in the plurality of cylinders slide on the inclined surface of the swash plate through the slippers connected to the heads of the pistons by the rotation of the cylinder block by the drive source such as the engine and the electric motor. Thus, the hydraulic oil is reciprocated and pressure-fed.

As such a swash plate type hydraulic pump, for example, the one disclosed in Japanese Patent Application Laid-Open No. 10-246177 discloses a swash plate angle slidably supported by a case by a semi-cylindrical sliding surface formed on the back. A cylinder that is provided with a swash plate whose tilt angle (swash plate angle) is adjustable by sliding the sliding surface relative to the case by an adjusting device, and is rotatable relative to the swash plate around the rotation axis. A plurality of cylinders are bored inside the block along the circumferential direction of the pump, and pistons are fitted in the cylinders so that they can reciprocate, and the pistons are moved in the cylinders as the swash plate and the cylinder block rotate relative to each other. By reciprocating, the working fluid is intermittently communicated with the suction hole (low-pressure fluid passage) and the discharge hole (high-pressure fluid passage), and the working oil (oil) sucked from the suction hole is pumped to the discharge hole. .

In such a swash plate type hydraulic pump, the pressure acting on the piston by the working fluid flowing in the high pressure fluid passage or the low pressure fluid passage is connected to the end portion of the piston by a spherical bearing. Pressure is received by a sliding surface with a case member formed on the back surface of the swash plate via a slipper and a thrust plate fixed to the swash plate.

[0005]

FIG. 3 shows a swash plate and a suction hole in a plane perpendicular to the pump rotation axis 25 in the conventional swash plate type hydraulic pump as disclosed in the above-mentioned JP-A-10-246177. It is a block diagram which shows the relationship position with a (low-pressure fluid passage) and a discharge hole (high-pressure fluid passage). In the figure, 8 is a swash plate (only the outer plane is shown), and 09 and 010 are suction holes and discharge holes which are perforated in a cocoon shape in a valve plate (not shown) and intermittently communicated with a piston (not shown). 9 and 10 are the suction hole 09 and the discharge hole 01.
0 is a suction passage and a discharge passage.

As described above, the high pressure fluid passage formed by the discharge hole 010 and the discharge passage 10 or the suction hole 0
The pressure acting on the piston by the working fluid flowing in the low-pressure fluid passage constituted by the suction passage 9 and the suction passage 9 is fixed to the slipper and the swash plate 8 connected to the end of the piston by the spherical bearing. The pressure is received by the sliding surface with the case member formed on the back surface of the swash plate 8 via.

However, in the prior art as shown in FIG. 3, the swash plate 8 is arranged axially symmetrically with respect to the pump rotation axis 25, so that the swash plate 8 for receiving the pressure acting on the piston is received. The sliding surface with the case member is also formed in axial symmetry with respect to the rotation axis 25. On the other hand, the pressure applied to the piston by the working fluid is such that the region on the high pressure fluid passage side formed by the discharge hole 010 and the discharge passage 10 is formed on the low pressure fluid passage side by the suction hole 09 and the suction passage 9. 3, the pressure on the sliding surface between the back surface of the swash plate 8 for receiving the piston pressure and the case member is higher than that of the pump rotation axis 25 shown by the diagonal line Y in FIG. High pressure is generated in the area.

Therefore, in such a prior art, the surface pressure of the sliding surface of the swash plate on the high-pressure fluid passage side of the pump rotation axis 25 becomes locally excessive, and the surface pressure of the sliding surface increases. Since no special lubricity improving means is applied to the part, abrasion or seizure is likely to occur on the sliding surface. There are problems such as.

In view of the above problems of the prior art, the present invention avoids the local increase of the surface pressure of the swash plate sliding surface in the portion near the high pressure fluid passage and improves the lubricity of the swash plate sliding surface. It is an object of the present invention to provide a swash plate type fluid machine in which abrasion and seizure are prevented from occurring on the sliding surface of the swash plate and the durability is improved.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an invention according to claim 1 in which a tilt angle (swash plate angle) is adjustable and a sliding surface formed on a back portion is provided. In a plurality of cylinders formed in a swash plate slidably supported by a case member and a cylinder block capable of relative rotation with respect to the swash plate around the rotation axis, and in the cylinder accompanying the relative rotation. A piston that is intermittently communicated with the high-pressure fluid passage and the low-pressure fluid passage by reciprocating the swash plate, and the pressure acting on the piston by the working fluid flowing in the high-pressure fluid passage or the low-pressure fluid passage is swash plate. In a swash plate type fluid machine configured to receive pressure on its sliding surface, the sliding surface of the swash plate is located at a portion of the sliding surface of the swash plate closer to the high pressure fluid passage than the rotation axis in the projection plane in the direction of the rotation axis. Pressurized fluid groove As well as several forms, proposes a swash plate-type fluid machine having a swash plate equalizer assembly which characterized in that it comprises a pressurized fluid passage for supplying pressurized fluid to the pressurized fluid groove.

In claim 1, preferably, as in claim 2, the pressurized fluid passage is connected to a high pressure fluid passage intermittently communicated with the piston, and a working fluid flowing in the high pressure fluid passage is connected to the high pressure fluid passage. It is preferable that the fluid is supplied to the pressurized fluid groove of the sliding surface through the pressurized fluid passage.

According to this invention, the pressure exerted on the piston by the working fluid becomes larger on the high pressure fluid passage side on the discharge side than on the low pressure fluid passage side on the suction side, and therefore the swash plate slide for receiving the piston pressure. Also on the surface, a pressure larger than that on the low pressure fluid passage side acts on the region from the piston side to the high pressure fluid passage side relative to the pump rotation axis. Therefore, in the invention, a plurality of pressurizing fluid grooves are formed at a portion of the sliding surface of the swash plate closer to the high-pressure fluid passage than the rotary shaft center on the projection plane in the pump rotary shaft direction, and the pressurizing fluid groove is formed. Since the pressurized fluid is supplied to the fluid groove through the pressurized fluid passage, the force of the pressurized fluid introduced into the plurality of pressurized fluid grooves formed on the swash plate sliding surface is applied from the piston side. Acting in the direction opposite to the pressure acting on the sliding surface of the swash plate,
The pressure from the piston side is offset.

Therefore, the surface pressure at the portion of the swash plate sliding surface near the high-pressure fluid passage can be reduced, and a local increase in the surface pressure at the swash plate sliding surface can be avoided. The surface pressure can be made uniform over the entire surface. Further, by supplying the pressurized fluid into the plurality of pressurized fluid grooves formed on the sliding surface of the swash plate, the lubricating action of the sliding surface of the swash plate is promoted and the lubricity is improved. As a result, it is possible to prevent the occurrence of wear or seizure on the swash plate sliding surface due to local excessive surface pressure on the high pressure fluid passage side of the swash plate sliding surface.

According to the present invention, the working fluid in the high pressure fluid passage is supplied to the pressurized fluid groove on the swash plate sliding surface, so that the pressure in the pressurized fluid groove is the pressure in the high pressure fluid passage. Therefore, even if the pressure in the high-pressure fluid passage increases, the surface pressure of the swash plate sliding surface is prevented from increasing, and the surface pressure of the swash plate sliding surface can always be maintained at the allowable surface pressure.

According to a third aspect of the present invention, in addition to the first aspect, a portion of the sliding surface of the swash plate closer to the low-pressure fluid passage than the rotation axis on the projection plane in the rotation axis direction. A second pressurized fluid groove is formed independently of the pressurized fluid groove, and is provided independently of the pressurized fluid passage to supply pressurized fluid to the second pressurized fluid groove. It is characterized by comprising two pressurized fluid passages.

In claim 3, preferably, as in claim 4, the pressurized fluid passage is connected to a low pressure fluid passage intermittently communicated with the piston, and a working fluid flowing in the low pressure fluid passage. Is supplied to the second pressurized fluid groove of the sliding surface through the second pressurized fluid passage.

According to the inventions of claims 3 and 4, claim 1,
In addition to forming a plurality of pressurized fluid grooves in a portion closer to the high-pressure fluid passage than the pump rotation axis, as in 2, the addition of the high-pressure fluid passage side to a portion closer to the low-pressure fluid passage than the pump rotation axis. A second pressurized fluid groove is formed independently of the pressurized fluid groove, and the pressurized fluid is supplied through a second pressurized fluid passage independent of the pressurized fluid passage on the high pressure fluid passage side. Since it is configured, the swash plate type hydraulic pump or the hydraulic pump can be easily applied to the swash plate type hydraulic motor or the hydraulic motor in which the high pressure side and the low pressure side are reversed, and the same as in the case of the hydraulic pump or the hydraulic pump, It is possible to obtain the effects of equalizing the surface pressure on the sliding surface of the swash plate and promoting the lubricating action of the sliding surface of the swash plate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, unless there is a specific description, and are merely illustrative examples. Nothing more.

FIG. 1 is a sectional view taken along the pump axis line showing the structure of a swash plate type hydraulic pump according to an embodiment of the present invention, and FIG. 2 is a view taken along the line A--A of FIG.

1 and 2 showing an embodiment of the present invention,
Reference numeral 1 denotes a pump shaft, which is connected to a drive source (not shown) such as an engine and an electric motor to be rotationally driven. Reference numeral 2 is a casing, and 3 and 4 are a base plate and an end plate fixed to the front and rear ends of the casing 2. Reference numeral 5 denotes a cylinder block fitted to the pump shaft 1 via a spline 18 and rotationally driven in synchronization with the pump shaft 1. A plurality of cylinders 6 are bored in the cylinder block 5 at equal intervals in the circumferential direction. 7 is each cylinder 6
It is a piston that is reciprocally slidably fitted in the piston. A bush (not shown) may be inserted into the cylinder 6 and the piston 7 may be reciprocally slidably fitted in the bush.

Reference numeral 11 denotes an oil supply / drain hole 011 of each of the cylinders 6.
The valve plate is disposed on the side and fixed to the end plate 4. As shown in FIG. 2, the valve plate 11 is provided with cocoon-shaped suction holes 09 and discharge holes 010 facing both sides of the rotary shaft center 25 of the pump. The end plate 4 has a suction passage 9 and a discharge passage 10 therein.
The suction passage 9 communicates with the suction hole 09 of the valve plate 11, and the discharge passage 10 has the discharge hole 010.
Is in communication with. Reference numerals 12 and 13 denote a base plate side bearing and an end plate side bearing that pivotally support the pump shaft 1. 16 is an oil seal and 19 is a pump chamber.

Reference numeral 8 is a swash plate attached to the base plate 3. Reference numeral 15 is a slipper, which is slidably attached to the base of each piston 7 through a spherical bearing 015 along a spherical surface. Reference numeral 17 is an annular retainer ring that supports the slippers 15. Reference numeral 14 denotes a thrust plate fixed to the surface of the swash plate 8 on the side of the slipper 15, and the slipper 15 slidably contacts the sliding surface of the thrust plate 14 on the side of the slipper 15.

The above construction is similar to that of the conventional swash plate type hydraulic pump. In the present invention, the area around the swash plate 8 is improved. 1 and 2, the swash plate 8 constitutes the case member by a semicylindrical sliding surface 8b formed on the back side, that is, on the side opposite to the thrust plate 14.
Slidably supported by (3a is the base plate 3
Sliding surface). Further, the swash plate 8 is configured so that the tilt angle (swash plate angle) can be adjusted by a swash plate angle adjusting mechanism 8a. Reference numeral 23 denotes a sliding surface 3 of the base plate 3 which is in sliding contact with the swash plate 8.
In the oil groove (pressurized fluid groove) engraved in a, as shown in FIG. 2, the discharge hole 010 and the discharge passage which are on the higher pressure side than the pump rotation axis 25 on the projection plane in the pump rotation axis direction. A plurality of them are formed along the sliding surface 3a with a predetermined length in the discharge hole 010 direction at a portion nearer to 10.

Reference numeral 22 designates the same number of oil holes as the oil grooves 23 communicated with the respective oil grooves 23, and a vertical oil passage 2 formed in the base plate 3 at a right angle to the rotation axis 25.
It branches from 1 and is connected to each oil groove 23. 20
Is an oil passage in the longitudinal direction that is bored in the casing 2 in the longitudinal direction, and is branched from the discharge passage 10 and connected to the oil passage 21 in the vertical direction. Therefore, the longitudinal oil passage 20 branched from the discharge passage 10 is communicated with the vertical oil passage 21, and a plurality of oil holes 22 are branched from the vertical oil passage 21 to form the discharge holes 010 and It will be connected to each oil groove 23 distributed on the discharge passage 10 side.

During operation of the hydraulic pump, when the pump shaft 1 is rotationally driven by a drive source such as an engine or an electric motor, the cylinder block 5 is rotated. Due to the rotation of the cylinder block 5, a spherical bearing 015 is attached to the head of the piston 7 that is reciprocally fitted in the cylinder 6.
The slipper 15 connected through the thrust plate 1
The piston 7 reciprocates in the cylinder 6 while rotating with the cylinder block 5 by sliding on the cylinder 4.

When the piston 7 moves to the left in the suction stroke in FIG. 1, the oil supply / drain hole 01 of the piston 7
1 communicates with the suction hole 09 of the valve plate 11, and oil is sucked from the suction passage 9. On the other hand, when the piston 7 moves to the right in the discharge stroke in FIG. 1, the oil supply / discharge oil hole 011 of the piston 7 is communicated with the discharge hole 09 of the valve plate 11, and the oil in the cylinder 6 is discharged by the piston 7. It is delivered to the passage 10. Even if water is used as the working fluid instead of the oil as the working fluid in the hydraulic pump, the hydraulic pump having the same structure as in FIGS. 1 and 2 can be configured.

During the operation of the hydraulic pump, the pressure acting on the piston 7 toward the swash plate 8 by the hydraulic oil is the discharge side, that is, the discharge hole 010 and the discharge passage 10 side is the suction side, that is, the suction hole 09 and the suction passage 9. Therefore, even in the sliding surfaces 8b and 3a on the side of the swash plate 8 that receives the piston pressure, in the region from the piston 7 side to the discharge side (high pressure fluid passage side) with respect to the pump rotation axis 25. A pressure larger than that on the suction side (low-pressure fluid passage side) acts.

However, in this embodiment, on the projection surface of the swash plate sliding surfaces 8b, 3a in the direction of the pump rotation axis 25, the discharge side (high pressure fluid passage side) of the rotation axis 25 is provided.
A plurality of oil grooves 23 are formed in the vicinity of the oil groove 23, and high-pressure discharge oil is discharged from the discharge passage 10 into the oil groove 23 in the longitudinal oil passage 2.
0, vertical oil passage 21 and the vertical oil passage 21
The oil is supplied to each oil groove 23 distributed in a region on the discharge side (high-pressure fluid passage side) of the pump rotation shaft center 25 through the oil hole 22 branched into a plurality of.

Therefore, the force of the high-pressure discharge oil introduced into the plurality of oil grooves 23 formed in the swash plate sliding surfaces 8b, 3a is applied from the piston 7 side to the swash plate sliding surfaces 8b, 3a.
It acts in the direction opposite to the pressure acting toward a and cancels the pressure from the piston 7 side. Therefore, the surface pressure at the portion of the swash plate sliding surfaces 8b, 3a closer to the discharge side (high-pressure fluid passage side) is reduced, and local increase in the surface pressure at the swash plate sliding surfaces 8b, 3a can be avoided. , The swash plate sliding surfaces 8b, 3
The surface pressure at a can be made uniform over the entire surface. Further, by supplying the discharged oil into the plurality of oil grooves 23 formed in the swash plate sliding surfaces 8b and 3a,
The lubricating action of the swash plate sliding surfaces 8b, 3a is promoted and the lubricity is improved.

Further, since the operating oil (discharging oil) on the discharge side (high pressure fluid passage side) is supplied to the oil groove 23 of the swash plate sliding surfaces 8b, 3a, the pressure in the oil groove 23 is the discharge side. The pressure on the (high pressure fluid passage side) is constantly balanced, and even if the pressure on the discharge side (high pressure fluid passage side) rises, the surface pressure on the swash plate sliding surfaces 8b, 3a does not increase. The surface pressure of the swash plate sliding surfaces 8b and 3a can be constantly maintained at the allowable surface pressure.

Furthermore, in the second embodiment, the first
In addition to the embodiment, as shown by the chain line in FIG. 2, in the projection surface of the swash plate sliding surfaces 8b, 3a in the pump rotation axis 25 direction, the suction hole 09 and A plurality of oil grooves 23 are formed in a portion near the suction passage 9 along the sliding surface 3a with a predetermined length in the suction hole 09 direction. Reference numeral 22 denotes an oil hole communicating with each of the oil grooves 23, the number of which is the same as that of the oil grooves 23, and a vertical oil passage 2 formed in the base plate 3 at a right angle to the rotation axis 25.
It branches from 1 and is connected to each oil groove 23. 20
Is an oil passage in the longitudinal direction which is bored in the casing 2 in the longitudinal direction, and is branched from the suction passage 9 and connected to the oil passage 21 in the vertical direction. The pressure-equalized oil system on the suction side, which extends from the suction passage 9 through the oil passages 20, 21, 22 to the oil groove 23, includes the discharge passage 10 through the oil passages 20, 21,
It is provided independently without crossing the pressure-equalizing oil system on the discharge side from 22 to the oil groove 23.

According to the second embodiment, in addition to forming a plurality of oil grooves 23 at a portion closer to the discharge side (high pressure fluid passage side) than the pump rotation axis 25 as in the second embodiment,
A second oil groove 23 is formed in a portion closer to the suction side (low-pressure fluid passage side) than the pump rotation axis 25, independently of the oil groove 23 on the discharge side (high-pressure fluid passage side). Since the working oil is supplied through the second pressure equalizing oil system independent of the pressure equalizing oil system on the (high pressure fluid passage side), the swash plate hydraulic pump or the hydraulic pump is divided into the high pressure side and the low pressure side. It can be easily applied to a swash plate type hydraulic motor or a hydraulic motor in which the above is reversed. As a result, even in the swash plate hydraulic motor or the hydraulic motor, as in the case of the hydraulic pump or the hydraulic pump, the surface pressure of the swash plate sliding surfaces 8b and 3a is made uniform and the swash plate sliding surfaces 8b and 3a are made uniform. The effect of promoting the lubricating action is obtained. The present invention can be applied to a swash plate hydraulic pump, a swash plate hydraulic motor, or a swash plate hydraulic motor in addition to the swash plate hydraulic pump in the above-described embodiment.

[0033]

As described above, according to the present invention, a plurality of pressurizing fluid grooves are provided in a portion of the sliding surface of the swash plate closer to the high pressure fluid passage than the rotary shaft center on the projection plane in the pump rotary shaft direction. Since it is formed and the pressurized fluid is supplied to the pressurized fluid groove through the pressurized fluid passage, the pressurized fluid introduced into the plurality of pressurized fluid grooves formed on the swash plate sliding surface is formed. The force from the piston acts in the direction opposite to the pressure acting on the sliding surface of the swash plate from the piston side, and the pressure from the piston side can be offset.

Therefore, the surface pressure at the portion of the sliding surface of the swash plate near the high-pressure fluid passage is reduced, and it is possible to avoid a local increase in the surface pressure at the sliding surface of the swash plate. The surface pressure can be made uniform over the entire surface. Further, by supplying the pressurized fluid into the plurality of pressurized fluid grooves formed on the sliding surface of the swash plate, the lubricating action of the sliding surface of the swash plate is promoted and the lubricity is improved. As a result, it is possible to prevent the occurrence of wear or seizure on the swash plate sliding surface due to local excessive surface pressure on the high pressure fluid passage side of the swash plate sliding surface.

According to the second aspect of the invention, since the working fluid in the high pressure fluid passage is supplied to the pressurized fluid groove on the sliding surface of the swash plate, the pressure in the pressurized fluid groove is the pressure in the high pressure fluid passage. Therefore, even if the pressure in the high-pressure fluid passage increases, the surface pressure of the swash plate sliding surface is prevented from increasing, and the surface pressure of the swash plate sliding surface can always be maintained at the allowable surface pressure.

Further, according to the third and fourth aspects,
In addition to forming a plurality of pressurized fluid grooves in a portion closer to the high-pressure fluid passage than the pump rotation axis as in claims 1 and 2,
A second pressurized fluid groove is formed in a portion closer to the low pressure fluid passage than the pump rotation axis, independently of the pressurized fluid groove on the high pressure fluid passage side, to form a pressurized fluid passage on the high pressure fluid passage side. Is configured to supply the pressurized fluid through the independent second pressurized fluid passage. Therefore, the swash plate hydraulic pump or the hydraulic pump is different from the high pressure side and the low pressure side in the swash plate hydraulic motor or the hydraulic motor. Can be easily applied to the swash plate, and the same effect as in the case of the hydraulic pump or the hydraulic pump can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along a pump axis line showing a structure of a swash plate hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is a diagram corresponding to FIG. 2 showing a conventional technique.

[Explanation of symbols]

1 pump shaft 3 base plate 3a Sliding surface 5 cylinder block 6 cylinders 7 pistons 8 swash plate 8b Sliding surface 9 Inhalation passage 09 suction hole 10 Discharge passage 010 Discharge hole 14 Thrust plate 15 slippers 21, 23 Oil passage 22 oil holes 25 Pump rotation axis

Continued front page    F-term (reference) 3H070 AA01 AA03 BB04 BB06 CC07                       CC27 DD46                 3H071 AA03 CC26 CC27                 3H084 AA08 AA16 AA45 AA51 BB06                       BB09 CC32 CC52 CC58

Claims (4)

[Claims] 1. A swash plate whose slant angle (swash plate angle) is adjustable and which is slidably supported by a case member by a sliding surface formed on the back, and the swash plate and a rotation axis. A piston that is fitted in a plurality of cylinders formed in a cylinder block that is relatively rotatable around it, and reciprocates in the cylinder due to the relative rotation to intermittently communicate with the high-pressure fluid passage and the low-pressure fluid passage; In the swash plate type fluid machine configured to receive the pressure acting on the piston by the working fluid flowing in the high pressure fluid passage or the low pressure fluid passage on the sliding surface of the swash plate, A plurality of pressurized fluid grooves are formed at a portion of the sliding surface that is closer to the high-pressure fluid passage than the rotational axis on the projection surface in the rotational axis direction, and pressurized fluid is supplied to the pressurized fluid groove. Provided with pressurized fluid passage A swash plate type fluid machine equipped with a swash plate pressure equalizing device. 2. The pressurized fluid passage is connected to a high pressure fluid passage intermittently communicated with the piston, and a working fluid flowing in the high pressure fluid passage is added to the sliding surface through the pressurized fluid passage. The swash plate type fluid machine provided with the swash plate pressure equalizing device according to claim 1, wherein the swash plate type fluid machine is configured to supply to the pressure fluid groove. 3. A second pressurized fluid groove is provided in a portion of the sliding surface of the swash plate closer to the low-pressure fluid passage than the rotational axis on the projection plane in the rotational axis direction. And a second pressurized fluid passage that is formed independently of the second pressurized fluid passage and that is provided independently of the pressurized fluid passage to supply the pressurized fluid to the second pressurized fluid groove. A swash plate type fluid machine provided with the swash plate pressure equalizing device according to claim 1. 4. The pressure fluid passage is connected to a low pressure fluid passage intermittently communicated with the piston, and the working fluid flowing in the low pressure fluid passage is slid through the second pressure fluid passage. A swash plate type fluid machine provided with a swash plate pressure equalizing device according to claim 3, wherein the swash plate pressure equalizing device is configured to supply to the second pressurized fluid groove of the surface.