Patent Application
20190145388
The present invention relates to a hydraulic rotary machine and a valve plate thereof.
JP1997-14125A discloses a swash-plate axial piston type pump including a cylinder block rotated by driving of a shaft through a spline, a piston inserted into a cylinder provided in the cylinder block in a freely reciprocating manner, a slipper provided on a base end of the piston, and a thrust plate having an inclined surface on which the slipper slides.
In the axial piston pump disclosed in JP1997-14125A, the cylinder block and the valve plate slide, and the piston reciprocates while rotating and thus, an operating liquid is suctioned into the cylinder through a suction port and the valve plate and compressed and is ejected via the valve plate and an ejection port.
In some hydraulic rotary machines, a surface of a sliding member is coated with a resin layer in order to reduce sliding resistance of the member sliding in an operation.
However, when the surface of the sliding member is coated with the resin layer, a manufacturing cost of the hydraulic rotary machine is increased.
The present invention has an object to reduce the manufacturing cost of the hydraulic rotary machine.
According to one aspect of the present invention, a hydraulic rotary machine includes a cylinder block to which a shaft is connected so as to be rotated with the shaft; a plurality of cylinders formed on the cylinder block, the plurality of cylinders being disposed at a predetermined interval in a circumferential direction of the shaft; a piston slidably inserted into the cylinder, the piston defining a volume chamber inside the cylinder; a shoe rotatably connected to a tip end of the piston; a swash plate with which the shoe is in sliding contact; a case accommodating the cylinder block; and a valve plate formed by a core member and a resin layer coating the core member, the valve plate being provided with a supply port through which an operating liquid supplied to the volume chamber passes and a discharge port through which an operating liquid discharged from the volume chamber passes, the valve plate being interposed between the cylinder block and the case. The valve plate has a sliding contact portion formed by the resin layer, the cylinder block being in sliding contact with the sliding contact portion; and a non-contact portion separated away from the cylinder block, and at least a part of the non-contact portion is an exposed portion where the core member is exposed.
Embodiments of the present invention will be described below by referring to the attached drawings.
First, by referring to
In the first embodiment, a case where the hydraulic rotary machine is a water-pressure rotary machine 100 using water as an operating liquid will be described. The water-pressure rotary machine 100 functions as a piston pump capable of supplying water as the operating fluid when a shaft 1 is rotated by power from an outside and a piston 6 is reciprocated and also functions as a piston motor capable of outputting a rotary driving force when the piston 6 is reciprocated by a fluid pressure of the water supplied from the outside and the shaft 1 is rotated. The water-pressure rotary machine 100 may function only as a piston pump or may function only as a piston motor.
In the description below, the case where the water-pressure rotary machine 100 is used as a piston pump is exemplified, and the water-pressure rotary machine 100 is called a “piston pump 100”.
The piston pump 100 includes the shaft 1 rotated by a power source, a cylinder block 2 connected to the shaft 1 and rotated with the shaft 1, and a case 3 accommodating the cylinder block 2 as illustrated in
To one end portion 1a of the shaft 1 protruding to the outside through an insertion hole 4a of the front cover 4, the power source is connected. The end portion 1a of the shaft 1 is rotatably supported by the insertion hole 4a of the front cover 4 through a first bush 16. The other end portion 1b of the shaft 1 is accommodated in an accommodating recess portion 5a provided on the end cover 5 and is rotatably supported through a second bush 17.
The cylinder block 2 has a through hole 2a through which the shaft 1 penetrates and is spline-connected with the shaft 1 through the through hole 2a. As a result, the cylinder block 2 is rotated with rotation of the shaft 1. The cylinder block 2 is rotatably supported by the case 3 through a slide bearing 15.
On the cylinder block 2, a plurality of cylinders 2b each having an opening portion on one end surface is formed in parallel with the shaft 1. The plurality of cylinders 2b is formed at a predetermined interval in a circumferential direction of the cylinder block 2. Into the cylinder 2b, the columnar piston 6 dividing a volume chamber 7 is inserted to be capable of reciprocating. A tip end side of the piston 6 protrudes from the opening portion of the cylinder 2b, and a spherical surface seat 6a is formed on the tip end portion.
Into the volume chamber 7, water is led through a supply passage 10 formed in the end cover 5. The water in the volume chamber 7 is discharged through a discharge passage 11 formed in the end cover 5.
The piston pump 100 further includes a shoe 8 rotatably connected to the spherical surface seat 6a of the piston 6 and in sliding contact with the spherical surface seat 6a, a swash plate 9 with which the shoe 8 is in sliding contact with rotation of the cylinder block 2, and a valve plate 20 interposed between the cylinder block 2 and the end cover 5.
The shoe 8 has a receiving portion 8a for receiving the spherical surface seat 6a formed on a tip end of each piston 6 and a circular flat plate portion 8b in sliding contact with the swash plate 9. An inner surface of the receiving portion 8a is formed having a spherical surface shape and is in sliding contact with an outer surface of the received spherical surface seat 6a. As a result, the shoe 8 is capable of angular displacement in any direction with respect to the spherical surface seat 6a.
The swash plate 9 is fixed to an inner wall of the front cover 4 and has a sliding contact surface 9a inclined from a direction perpendicular to an axis of the shaft 1. The flat plate portion 8b of the shoe 8 is in surface contact with the sliding contact surface 9a.
The valve plate 20 is a disc member formed by a core member 21 made of metal and a resin layer 22 coating the core member 21.
The valve plate 20 has, as illustrated in
In the valve plate 20, the first land portion 30 and the second land portion 35 are formed having a similar shape. Thus,
In the valve plate 20, a supply port 20a connecting the supply passage 10 and the volume chamber 7 and allowing passage of water to be supplied to the volume chamber 7, a discharge port 20b connecting the discharge passage 11 and the volume chamber 7 and allowing passage of water discharged from the volume chamber 7, and a shaft insertion hole 20c formed at the center of the valve plate 20 and into which the shaft 1 is inserted are provided.
The first land portion 30 is, as illustrated in
The first land portion 30 is divided by the supply port 20a and the discharge port 20b into the first outer-side land portion 31 and a first inner-side land portion 32. The first outer-side land portion 31 and the first inner-side land portion 32 are connected by a first intermediate portion 33 provided between the supply port 20a and the discharge port 20b in the circumferential direction.
By adjusting a width of the first land portion 30 in the radial direction, sliding resistance between the valve plate 20 and the cylinder block 2 is adjusted, and a surface pressure of the valve plate 20 to the cylinder block 2 is adjusted. By adjusting the surface pressure of the valve plate 20 to the cylinder block 2, sealing performance between the cylinder block 2 and the valve plate 20 is adjusted. Thus, by setting the width of the first land portion 30 in the radial direction appropriately, both the sliding resistance and the sealing performance between the valve plate 20 and the cylinder block 2 are set appropriately.
The second land portion 35 is formed annularly by the resin layer 22 coating the surface of the core member 21 and is brought into contact with the end cover 5 of the case 3. Similarly to the first land portion 30, the second land portion 35 is divided by the supply port 20a and the discharge port 20b into a second outer-side land portion 36 and a second inner-side land portion 37. Moreover, the second outer-side land portion 36 and the second inner-side land portion 37 are connected by a second intermediate portion 38 provided between the supply port 20a and the discharge port 20b in the circumferential direction. The valve plate 20 is fixed to the end cover 5 in a state where the second land portion 35 is in contact with the end cover 5.
By setting a width of the second land portion 35 in the radial direction appropriately, the surface pressure of the valve plate 20 to the end cover 5 is adjusted. As a result, sealing performance between the valve plate 20 and the end cover 5 of the case 3 is ensured.
The outer-side non-contact portion 40 is, as illustrated in
The outer-side non-contact portion 40 has, as illustrated in
As illustrated in
As described above, the exposed portions 50 are provided on the outer-side non-contact portion 40 and the inner-side non-contact portion 45 not in contact with either of the cylinder block 2 or the case 3. Even if the exposed portion 50 is provided on the outer-side non-contact portion 40 and the inner-side non-contact portion 45, sliding between the cylinder block 2 and the valve plate 20 is not affected. That is, an entire area of the exposed portion 50 can be easily increased without impairing performances of the piston pump 100.
The supply port 20a and the discharge port 20b are, as illustrated in
The port resin layer 22a is, as illustrated in
The shaft insertion hole 20c is defined by the resin layer coating the inner peripheral surface of a circular base through hole 21c provided in the core member 21 (see
Subsequently, an operation of the piston pump 100 will be described.
When the shaft 1 is rotated/driven by power from an outside, and the cylinder block 2 is rotated, the flat plate portion 8b of each shoe 8 slides with respect to the swash plate 9, and each piston 6 reciprocates in the cylinder 2b with a stroke amount according to an inclination angle of the swash plate 9. By means of reciprocating of each piston 6, the volume of each volume chamber 7 is increased/decreased.
Into the volume chamber 7 expanding by rotation of the cylinder block 2, water is led through the supply passage 10 of the end cover 5 and the supply port 20a of the valve plate 20. The water suctioned into the volume chamber 7 has its pressure increased by contraction of the volume chamber 7 by rotation of the cylinder block 2 and is ejected through the discharge port 20b of the valve plate 20 and the discharge passage 11 of the end cover 5. As described above, in the piston pump 100, suction and ejection of the water is continuously performed with rotation of the cylinder block 2.
Subsequently, a manufacturing method of the valve plate 20 will be described by referring to
First, as illustrated in
Subsequently, as illustrated in
In
Moreover, the core member 21 is supported by the support pins 62a and 62b on the base intermediate portion 21d provided between the supply base hole 21a and the discharge base hole 21b in the circumferential direction, that is, on the outer side and the inner side in the radial direction of portions corresponding to the first and second intermediate portions 33 and 38 after coating of the resin layer 22.
Subsequently, a resin material is injected into the cavity 63 from an injection port (not shown) so as to mold-form the resin layer 22 on the core member 21.
Here, since the core member 21 has the outer side and the inner side with the supply base hole 21a and the discharge base hole 21b supported by the support pins 62a and 62b, even if the resin material at a high pressure and a high temperature is injected, deformation of the core member 21 caused by an injection pressure and a heat of the resin material is prevented.
Moreover, the base intermediate portion 21d is located between the supply base hole 21a and the discharge base hole 21b formed as grooves in the circumferential direction, this is a portion with strength smaller than those of the other portions in the core member 21. Since the outer side and the inner side in the radial direction of such base intermediate portion 21 are supported by the support pins 62a and 62b, deformation of the core member 21 in the mold-forming is prevented more reliably.
After the resin material is mold-formed, when the upper die 60 and the lower die 61 are removed, as illustrated in
Subsequently, by cutting/machining the resin layer 22 at the outer side portion of the core member 21 including the exposed portion 50 and a center portion of the core member 21 including the exposed portion 50, the outer-side non-contact portion 40 and the inner-side non-contact portion 45 are formed. As a result, as illustrated in
Subsequently, by cutting/machining a part of the resin layer 22 filled in the base hole, the supply port 20a, the discharge port 20b, and the shaft insertion hole 20c are formed.
By means of the aforementioned processes, the valve plate 20 is manufactured.
As described above, by supporting both the outer side and the inner side of the core member 21 in the radial direction by the support pins 62a and 62b, deformation of the core member 21 in the mold-forming can be prevented more reliably, and the exposed portion 50 is formed by removing the support pins 62. Thus, while mold-forming with a small coating amount of the resin material, the valve plate whose deformation is prevented can be obtained.
Subsequently, a variation of the first embodiment will be described.
In the aforementioned first embodiment, the water-pressure rotary machine 100 using water as the operating liquid has been described. Instead of this, the operating liquid may be an operating oil or any other things.
Moreover, in the aforementioned first embodiment, the case where the water-pressure rotary machine 100 is a fixed displacement piston pump in which the inclination angle of the swash plate 9 is fixed has been described. Instead of this, the water-pressure rotary machine 100 may be a variable displacement type capable of changing the inclination angle of the swash plate 9.
In the aforementioned first embodiment, the eight exposed portions 50 are provided on the outer-side non-contact portion 40 on the outer side of the valve plate 20, and the four exposed portions 50 are provided on the inner-side non-contact portion 45 on the inner side. On the valve plate 20, the number of the exposed portions 50 is not limited to them, but an arbitrary number of the exposed portions 50 can be provided.
Moreover, in the aforementioned first embodiment, the resin layer 22 is molded in the base hole formed in the core member 21 in advance, and the molded resin layer 22 is machined so as to form the supply port 20a, the discharge port 20b, and the shaft insertion hole 20c. In order to prevent entry of water into a space between the core member 21 and the resin layer 22, the supply port 20a, the discharge port 20b, and the shaft insertion hole 20c are preferably formed as described above. However, instead of this, it may be so configured that the base hole is not machined in advance in the core member 21 but the resin layer 22 is molded on the core member 21 and then, the resin layer 22 is machined together with the core member 21 so as to form the supply port 20a, the discharge port 20b, and the shaft insertion hole 20c.
Moreover, in the aforementioned first embodiment, the first land portion 30 and the second land portion 35 are formed having a similar shape having the same radial width. Instead of this, the first land portion 30 and the second land portion 35 may have shapes different from each other.
Moreover, in the aforementioned first embodiment, the valve plate 20 has the second land portion 35, and by setting the radial width of the second land portion 35 appropriately, sealing performance between the valve plate 20 and the end cover 5 of the case 3 is ensured. Instead of this, it may be so configured that the valve plate 20 does not have the second land portion 35 and the land portion is provided on the end cover 5.
Moreover, the hydraulic rotary machine 100 may be configured such that both the valve plate 20 and the end cover 5 do not have the land portion. In this case, the valve plate 20 is in contact with the end cover 5 on the whole end surface faced with the end cover 5. Even in this case, the exposed portion 50 only needs to be provided on the outer-side non-contact portion 40 with which the cylinder block 2 is not in sliding contact. That is, the exposed portion 50 may be provided on a portion in contact with the end cover 5 as long as it is not provided on the first land portion 30 with which at least the cylinder block 2 is in sliding contact.
According to the aforementioned first embodiment, the following effects are exerted.
In the piston pump 100, the exposed portion 50 is provided on the outer-side non-contact portion 40 not in contact with the cylinder block 2 or the case 3. The exposed portion 50 supports the core member 21 by the support pins 62a and 62b in mold-forming of the resin layer 22 and is formed by removing the support pins 62a and 62b after the mold-forming. As described above, by mold-forming the resin layer 22 by supporting the core member 21 of a portion with which the cylinder block 2 is not in sliding contact, the exposed portion 50 thus formed does not affect sliding between the cylinder block 2 and the valve plate 20. Thus, an area of the core member 21 supported in the mold-forming, that is, an area of the core member 21 on which the resin layer 22 is not molded and which is exposed after the mold-forming can be increased. Thus, by increasing the area of the exposed portion 50, deformation in the mold-forming is prevented, and the valve plate 20 with a smaller coating amount of the resin material in the mold-forming can be obtained. Therefore, while the performances of the piston pump 100 are ensured, the manufacturing cost of the piston pump 100 can be reduced.
Moreover, in the valve plate 20, the exposed portion 50 is provided also on the inner-side non-contact portion 45 not in contact with the cylinder block 2 or the case 3. Thus, an area supported by the support pins 62a and 62b in the mold-forming, that is, the area of the core member 21 exposed after the mold-forming can be further increased. Therefore, the valve plate 20 whose deformation is prevented more reliably and having a smaller coating amount of the resin material can be obtained, and the manufacturing cost of the piston pump 100 can be further reduced.
Moreover, in the valve plate 20, the outer side and the inner side in the radial direction of the base intermediate portion 20d with relatively lower strength is supported by the support pins 62a and 62b, and the exposed portion 50 is provided on the outer sides and the inner sides in the radial direction of the first and second intermediate portions 33 and 38. Thus, the valve plate 20 with deformation of the core member 21 prevented more reliably can be obtained.
Subsequently, a piston pump 200 according to a second embodiment of the present invention will be described by referring to
In the aforementioned first embodiment, the exposed portion 50 is provided on a part of the outer-side non-contact portion 40 and also provided on a part of the inner-side non-contact portion 45. Instead of this, a valve plate 120 of the piston pump 200 is different from the aforementioned first embodiment in a point that all of an outer-side non-contact portion 140 is formed as an exposed portion, and all of an inner-side non-contact portion 145 is formed as an exposed portion.
As illustrated in
A shaft insertion hole 120c is a through hole formed in the core member 21 in advance and its inner periphery is not covered by the resin layer 22 as in the aforementioned first embodiment. The shaft insertion hole 120c has an inner diameter larger than an outer diameter of the shaft 1 and is formed so that the shaft 1 is not brought into contact. Thus, even if the inner periphery of the shaft insertion hole 120c is not covered by the resin layer 22, the shaft 1 and the valve plate 20 are not in contact with each other, and the performances of the piston pump is not lowered.
In manufacture of the valve plate 120, unlike the manufacturing method in the first embodiment in which the core member 21 is supported by the support pins 62a and 62b, the core member 21 is, as illustrated in
Here, as in the aforementioned first embodiment, if the outer peripheral surface of the valve plate 20 is coated with the resin layer 22 so as to be covered, friction resistance between the core member 21 and the resin layer 22 becomes larger and thus, the core member 21 and the resin layer 22 do not perform relative rotation easily.
On the other hand, if the outer peripheral surface is not covered by the resin layer 22 as in the valve plate 120, there is a concern that the core member 21 and the resin layer 22 perform relative rotation. However, in the valve plate 120, similarly to the valve plate 20 according to the aforementioned first embodiment, since the supply port 20a and the discharge port 20b are defined by the port resin layer 22a, and the port resin layer 22a is locked by the supply port 20a and the discharge port 20b, the relative rotation between the core member 21 and the resin layer 22 can be regulated.
According to the second embodiment as above, the effects similar to those in the aforementioned first embodiment are exerted, and the following effects are also exerted.
In the valve plate 120, the entire outer-side non-contact portion 140 is the exposed portion and the entire inner-side non-contact portion 145 at the center is the exposed portion. Thus, the resin amount in the mold-forming of the valve plate 120 can be further reduced. Moreover, in the valve plate 120, mold-forming is performed while the entire outer periphery corresponding to the outer-side non-contact portion 140 is supported by the clamp members 162a and 162b, and the center portion corresponding to the entire inner-side non-contact portions 45 is supported by the columnar members 163a and 163b. As described above, since the core member 21 is supported by a larger area, deformation of the core member 21 in the mold-forming can be prevented more reliably. Therefore, in the piston pump 200, deformation in the mold-forming of the resin layer 22 can be prevented more reliably, and the valve plate 120 with the smaller coating amount of the resin material can be obtained, and the manufacturing cost of the piston pump can be further reduced.
The constitutions, the actions, and the effects of the embodiments of the present invention will be described below altogether.
Each of the piston pumps 100 and 200 include the cylinder block 2 to which the shaft 1 is connected and rotated with the shaft 1, the plurality of cylinders 2b formed on the cylinder block 2 and disposed at a predetermined interval in the circumferential direction of the shaft 1, the piston 6 slidably inserted into the cylinder 2b and dividing the volume chamber 7 inside the cylinder 2b, the shoe 8 rotatably connected to the tip end of the piston 6, the swash plate 9 with which the shoe 8 is in sliding contact, the case 3 accommodating the cylinder block 2, the valve plate 20 or 120 formed by the core member 21 and the resin layer 22 coating the core member 21, provided with the supply port 20a through which the water supplied to the volume chamber 7 passes and the discharge port 20b through which the water discharged from the volume chamber 7 passes, and interposed between the cylinder block 2 and the end cover 5 of the case 3. The valve plate 20 or 120 has the first land portion 30 formed by the resin layer 22 and with which the cylinder block 2 is in sliding contact and the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) separated away from the cylinder block 2, and at least a part of the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) is the exposed portion 50 where the core member 21 is exposed.
In this constitution, the exposed portion 50 is provided on the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) with which the cylinder block 2 is not in sliding contact in the valve plate 20 or 120. As a result, the coating amount of the resin material is reduced without imparing the performances of the piston pump 100 or 200. Therefore, the manufacturing cost of the piston pump 100 or 200 can be reduced.
Moreover, in the piston pump 100 or 200, the supply port 20a and the discharge port 20b are defined by the port resin layer 22a coating the inner peripheral surfaces of the supply base hole 21a and the discharge base hole 21b provided in the core member 21, respectively, and the port resin layer 22a is provided continuously to the first land portion 30.
According to this constitution, entry of the water passing through the supply port 20a and the discharge port 20b into a space between the core member 21 and the resin layer 22 is prevented. Moreover, since the port resin layer 22a is locked by the inner peripheral surfaces of the supply base hole 21a and the discharge base hole 21b of the core member 21, the relative rotation of the first land portion 30 with respect to the core member 21 by sliding resistance between the cylinder block 2 and the valve plate 20, 120 is regulated.
Moreover, in the piston pump 100 or 200, the non-contact portion has the outer-side non-contact portion 40 or 140 provided closer to the outer side in the radial direction than the first land portion 30, and at least a part of the outer-side non-contact portion 40 or 140 is the exposed portion 50.
Moreover, in the piston pump 100 or 200, the non-contact portion has the inner-side non-contact portion 45 or 145 provided on the inner side in the radial direction of the first land portion 30, and at least a part of the inner-side non-contact portion 45 or 145 is the exposed portion 50.
In these constitutions, the exposed portion 50 is provided on the outer-side non-contact portion 40 or 140 and the inner-side non-contact portion 45 or 145 not in contact wither with the cylinder block 2 or the case 3. Thus, the coating amount of the resin material is reduced without imparing the performances of the piston pump 100.
Moreover, in the piston pump 100 or 200, at least a part of the core member 21 exposed in the exposed portion 50 is the support portion supported in the mold-forming of the resin layer 22.
In this constitution, a part of the core member 21 supported in the mold-forming becomes the exposed portion 50 exposed to the outside after the mold-forming. Thus, by increasing the amount of the exposed portion, the area supported in the mold-forming increases, whereby deformation of the core member 21 in the mold-forming is prevented, and the resin amount in the mold-forming is reduced.
Moreover, in the piston pump 100 or 200, the supply port 20a and the discharge port 20b are formed as arc-shaped grooves, respectively, and the exposed portion 50 which is the support portion is provided on at least one of the outer side in the radial direction and the inner side in the radial direction of the first intermediate portion 33 and the second intermediate portion 38 provided between the supply port 20a and the discharge port 20b in the circumferential direction.
According to this constitution, since at least one of the outer side in the radial direction and the inner side in the radial direction of the first intermediate portion 33 and the second intermediate portion 38 with relatively lower strength is made the support portion, deformation in the mold-forming can be prevented more reliably.
Moreover, in the piston pump 200, the whole non-contact portion (the outer-side non-contact portion 40, 140, the inner-side non-contact portion 45, 145) is formed as the exposed portion.
According to this constitution, while deformation of the core member 21 in the mold-forming is prevented more reliably, the resin amount in the mold-forming is further reduced.
Moreover, the valve plate 20, 120 interposed between the cylinder block 2 and the case 3 of the piston pump 100 or 200 and formed by the core member 21 and the resin layer 22 coating the core member 21 has the first land portion 30 formed by the resin layer 22 and with which the cylinder block 2 is in sliding contact and the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) separated away from the cylinder block 2, and at least a part of the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) is the exposed portion 50 where the core member 21 is exposed.
In this constitution, the exposed portion 50 is provided on the non-contact portion (the outer-side non-contact portion 40 or 140, the inner-side non-contact portion 45 or 145) with which the cylinder block 2 is not in sliding contact in the valve plate 20 or 120. As a result, the coating amount of the resin material is reduced without imparing the performances of the piston pump 100 or 200. Therefore, the manufacturing cost of the piston pump 100 or 200 can be reduced.
The embodiments of the present invention described above are merely illustration of some application examples of the present invention and not of the nature to limit the technical scope of the present invention to the specific constructions of the above embodiments.
The present application claims a priority based on Japanese Patent Application No. 2015-183215 filed with the Japan Patent Office on Sep. 16, 2015, all the contents of which are hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-183215 | Sep 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/077189 | 9/14/2016 | WO | 00 |
