JPS59120786A - Radial piston type hydraulic rotary machine - Google Patents

Abstract

PURPOSE:To facilitate capacity varying operation with a compact structure by installing a mechanism for shifting a cam ring having the inner peripheral surface in a cam surface for guiding a piston which is in eccentricity for a distribution shaft, in slidable ways along the inner wall of a casing. CONSTITUTION:The pistons 34 and 37 installed in a cylinder chamber are displaced in sliding by operating an outside selector valve, and a control pin 39 is shifted, and a cam ring 32 is turned. A rotor 3 is fitted onto the distribution shaft 7 of a casing 3 and a cylinder 4 is projected radially on the rotor 3, and a piston 5 is installed in free reciprocation into the cylinder, and the outer peripheral surface of the cam ring 32 forms a cam surface 32B for guiding the piston 5 which is in eccentricity for the distribution shaft 7. Therefore, the capacity can be varied by the turning of the cam ring 32, and the space for the transfer of the cam ring 32 on the casing 31 can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial piston type hydraulic motor equipped with a variable capacity mechanism and a hydraulic rotary machine used as a hydraulic pump.

1 and 2 show a hydraulic motor as a radial piston type hydraulic rotating machine according to the prior art.

In the figure, ] denotes a front casing IA, a rear casing IB, and each of the casings IA.

The casing consists of a cylindrical casing IC provided between 13 and 13. A cam ring 2 is disposed inside the casing 1, and a rotor 3 is rotatably disposed inside the cam ring 2. The rotor 3 has a plurality of cylinders 4, 4 . . . are bored, and a piston 515, . . . is slidably provided in each cylinder 4. Reference numeral 6 denotes a seat that swingably supports the tip of the piston 5, and the shoe 6 is brought into sliding contact with two cam surfaces formed on the inner circumferential wall of the cam ring 2. Reference numeral 7 denotes a distribution shaft provided through the rear casing IB, and the distribution shaft 7 is slidably fitted into a shaft insertion recess 3 formed at the rotation center of the rotor 3, thereby allowing the rotor 3 to rotate freely. I support it. Further, the distribution shaft 7 has a pair of suction and discharge ports 8 and 9.
is bored, and is configured so that supply and discharge of pressure oil can be switched as the rotor 3 rotates.

Next K, 10.11 are cylinder chambers formed on both left and right sides of the cylindrical gauging IC, and inside each cylinder chamber 10, If? i-pistons 12, 13 are each slidably arranged. The tip surfaces of each piston 12, 13 are in contact with the outer peripheral surface of the cam ring 2 at left and right positions, and the outer peripheral surface of the cam ring 2 has guide surfaces ID formed at the upper and lower positions in FIG.

The cam ring 2 is in contact with the ID, and thereby the cam ring 2 is supported at four points. Furthermore, oil chambers 14 and 15 are formed in the cylinder chambers 10 and I:1, respectively, in which hydraulic pressure acts on the end surfaces of the pistons 12 and 13.
Inside are the inner wall of the cylinder chamber 10.11 and the piston 12.1.
Spring 16 and 17 are respectively stretched between the end faces of 3,
Each piston 12, 13 is always biased in the direction of pressing against the cam ring 2 by the springs 16, 17. Further, pipes 18 and 19 are connected to the oil chambers 14 and 15, respectively, and the other ends of the pipes 18 and 19 are connected to a switching valve 20. In addition, in the figure, 23 indicates a rotating shaft mounting part provided integrally with the printer 3, and the rotating shaft mounting part 23 protrudes from inside the front casing to the outside. By attaching a rotating shaft thereto, the rotating shaft is rotated by the rotor 3.

The hydraulic rotary machine according to the prior art has the above-mentioned configuration, and next, the operation as a hydraulic motor will be explained.

Of the suction/discharge ports 8 and 9 formed on the distribution shaft 7, for example, port 8 is connected to a hydraulic pump, and port 9 is connected to a tank, so that pressure oil from the hydraulic pump is fed into the cylinder 4 through port 8. supply to. This presses the piston 5, but if the rotor 3 is eccentric with respect to the cam ring 2, the piston 5 is forced to protrude from the cylinder 4, and the shoe 6 attached to the piston 5 is pressed against the cam ring 2. The rotor 3 rotates by slidingly guiding it along the two cam surfaces. When the rotor 3 rotates half a rotation, the cylinder 4 communicates with the other port 9, the piston 5 enters the cylinder 4, and the pressure oil in the cylinder 4 is returned to the tank via the port 9. In this manner, by intermittently communicating the cylinder 4 with the port 8.degree. 9, the rotor 3 is rotated, and the rotating shaft fitted into the receiving portion 23 is rotationally driven.

In this case, the piston 5 strokes within the cylinder 4 by an amount corresponding to the eccentricity of the rotor 3, and the displacement by the piston 5, that is, the capacity of the hydraulic motor changes depending on the eccentricity of the rotor 3. Therefore, in order to change the capacity of the hydraulic motor, the switching valve 20 is switched to the state shown in FIG. It is refluxed to tank 22. This causes the piston 13 to move into the cylinder chamber 11.
At the same time, the piston 12 enters into the cylinder chamber 10, and the cam ring 2 is slid to the left in the figure along the guide surface ID. As a result, the amount of eccentricity of the rotor 3 with respect to the cam ring 2 increases, and the stroke amount of the piston 5, that is, the capacity of the hydraulic motor can be increased.

On the other hand, when the switching valve 20 is switched to the left position in FIG.
1, the cam ring 2 is displaced to the right in the figure, the amount of eccentricity decreases, and the capacity changes in the direction of decreasing.

However, in the hydraulic rotating machine according to the prior art described above,
Since the capacity of the cam ring 2 can be varied by eccentrically displacing the cam ring 2, the length inside the casing 1 in the eccentric direction needs to be long enough to enable eccentric movement of the cam ring 2. There is. Moreover, since the cam ring 2 receives the reaction force of the piston 5 via the sea 6, it is necessary to increase the wall thickness of the cam ring 2 to strengthen its rigidity. It has the disadvantage of being large. Furthermore, since the pressing force of each piston 5 against the cam ring 2 changes depending on the hydraulic pressure within the cylinder 4 and the position of the cylinder 4, the pressing force varies while the piston 501 rotates. As a result, when the motor rotates at high speed, the cam ring 2 is connected to the piston 1.
．． The piston 12.13 violently vibrates in the eccentric direction together with the piston 13, causing noise, and the sliding part between the piston 12.13 and the cylinder chamber 10.11 has the disadvantage of causing seizure.

Also, when the motor rotates at low speed, the pistons 1.2 and 13
There is also the disadvantage that an uneven load is applied to the capacitor, making it difficult to change the capacity smoothly.

The present invention has been made in order to eliminate the drawbacks of the prior art described above, and provides a radial piston type hydraulic rotating machine that has a compact structure and is capable of performing a capacity change operation in a stable state. The purpose is to

In order to achieve the above-mentioned object, a radial piston type hydraulic rotating machine according to the present invention includes: a distribution shaft provided protruding within a casing; a rotor rotatably fitted into the distribution shaft within the casing; A plurality of cylinders are drilled radially in the rotor, a piston is provided in each cylinder so as to be able to reciprocate, and the outer circumferential surface is coaxial with the distribution shaft and is slidably provided on the inner circumferential wall of the casing, and the inner circumferential surface The cam ring is eccentric with respect to the distribution shaft and serves as a cam surface for guiding the piston, and the cam ring is comprised of a cam ring that slides the cam ring along the inner wall of the casing. It is.

When changing the capacity of a hydraulic rotating machine having such a configuration, the cam ring rotation mechanism is driven to rotate the cam ring along the inner circumferential wall of the casing.

Therefore, in the radial piston type hydraulic rotating machine according to the present invention, the entire capacity of the cam ring can be changed by rotating the entire cam ring along the inner wall of the casing. Since there is no need to provide this, and the cam ring is supported in contact with the casing, there is no need to make the cam ring rigid enough to be thick enough to absorb the hydraulic reaction force of the piston. For this reason, the radial length of the hydraulic rotary machine can be shortened, and its configuration is It can be made into a specific item. In addition, since the cam ring is not configured so that its entire circumference is in contact with the casing and is supported by hydraulic pressure, it does not generate large vibration noises during its operation, and its operation is stable. , there is no risk of a large load being applied to the cam ring rotation mechanism and impairing smooth capacity changes.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6. In this figure, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and the explanation thereof will be omitted. 31 indicates a casing, and the casing 31 is a front casing 31. A, a rear casing 31B, and a cylindrical casing 31C provided between the casings 31A and 31B. The cylindrical casing 31C does not have the cylinder chamber 10.11 or the guide surface 1D shown in the prior art, and its inner peripheral wall 31D has a circular shape coaxial with the distribution shaft 7. 32 is a cam ring disposed inside the casing 31;
The cam ring 32 has a circular outer circumferential surface coaxial with the distribution shaft 7, and serves as a sliding surface 32A that slidably contacts the inner circumferential wall 31D of the cylindrical casing 31C over almost its entire circumference.

On the other hand, the inner peripheral surface of the cam ring 32 has a circular shape eccentric to the distribution shaft 7, and serves as a cam surface 32B that slides and guides the sear 6.

A cylinder chamber 33 is provided inside the rear casing 31B. A piston 34 is slidably provided in the cylinder chamber 33, and an oil chamber 35 is formed by the piston 34 in the cylinder chamber 33.

A spring 36 is installed in the oil chamber 35 between the inner wall of the cylinder chamber 33 and the piston 34, and the piston 34 is always biased to the left in FIG.

37 is another piston provided on the same axis as the piston 34, the tip end of the other piston 37 contacts the piston 34, and the base end of the piston 37 contacts the rear casing 31.
It faces into the oil chamber 38 formed at B. 39 is a control pin protruding from the side of the cam ring 32;
The tip of the control pin 39 engages with a groove 34A formed in the piston 34. These cylinder chamber 33, piston 34, 37, oil chamber 38, control bottle 39
A cam ring rotation mechanism is constructed by the above.

Furthermore, 40 is a switching valve that controls the sliding displacement of the piston 34.
2, as well as oil passages 43, 44 and oil holes 45.
, 46, respectively, communicate with the oil chambers 35, 38. When the switching valve 40 is in the switching position (A), the oil chamber 38 is connected to the pump 41, and the oil chamber 35 is connected to the tank 4.
It is designed to be connected to 2. On the other hand, when the switching valve 4o is in the switching position (b), both the oil chambers 35 and 38 are connected to the tank 42.

The radial piston type hydraulic rotating machine according to the present invention has the above-described configuration, and since the cam surface 32.8 of the cam ring 32 is eccentric with respect to the distribution shaft 7, its operation as a hydraulic motor is In terms of itself, there is no particular difference from the prior art described above.

When the eccentric direction of the cam surface 32B of the cam ring 32 with respect to the distribution shaft 7 is on the line A-A connecting the switching parts of the ports 8 and 9, as shown in FIG. 3, the capacity of the hydraulic motor is maximized. . On the other hand, if the cam ring 32 is rotated from this state, the eccentric direction of the cam surface 32B with respect to the distribution shaft 7 will change, and the most fully inserted position O and the most protruded position of the piston 5 in the cylinder 4 will switch between the ports 8 and 9. Since the position of the hydraulic motor is shifted from the position of the hydraulic motor, the capacity of the hydraulic motor is reduced.

Therefore, the relationship between the rotation of the cam ring 32 and the capacity of the hydraulic motor will be explained based on FIG. 6. FIG. 6(A) shows a state in which the eccentric direction of the cam surface 32B of the cam ring 32 is on the line A-A connecting the switching parts of the ports 8 and 9, and FIG. 6(B) shows the state in which the eccentric direction of the cam surface 32B of the cam ring 32 The eccentric direction of
- The rotor 3 and the distribution shaft 7 are shown expanded by an angle θ shifted from the line A. It is assumed that port 8 is connected to a hydraulic pump, and port 9 is connected to a tank.

In the state shown in FIG. 6(a), the piston 5 communicates with the suction/exhaust port 8 from the position where it enters the cylinder 4 most to the position where it protrudes most from the cylinder 4. After sucking in the pressure oil, at the most protruding position of the piston 5, the cylinder 4 switches from port 8 to port 9 and starts to enter, and the cylinder 4 continues to move until it switches to port 8 again at the most fully inserted position.
Continue to drain the pressure oil inside. Therefore, the flow rate Q per revolution of the hydraulic motor in this state is Q=! ! -D2×NxS (D is the inner diameter of the piston 5, N is the number of pistons 5, and S is the stroke of the piston 5.) In this state, the capacity of the hydraulic motor per revolution is at its maximum.

On the other hand, when the cam ring 32 is rotated by an angle θ from the above-mentioned state, the rotor 3
The phase of the switching portion between the intake and exhaust ports 8 and 9 is also shifted by an angle θ. As a result, the piston 51d enters the extension stroke from the most fully inserted position into the cylinder 4. After entering, it communicates with the date 8, and while communicating with the port 8, it reaches the most extended position, and then starts the approach stroke. port 8 to port 9 after
Switch to .

Therefore, the stroke of the piston 5 is apparently reduced by the stroke S (which corresponds to the distance between the position at the time of switching from port 9 to port 8 and the position at the time of switching from port 8 to port 9). , the flow rate Q' of the hydraulic motor in this state is Q'='D2XNX S(θ)
Tosuhiro S(no-R(π-θ)-R(θ) R(no"")/L"E"gk' 0 -
acos θ (L is the distance from the center of rotation of C-6 to its center of revolution, R (is the distance between the center of rotation of the rotor at the position of θ and the center of rotation of C-6, and ε is the eccentricity of rotor 3. ) and 10,000 respectively. Therefore, the flow rate Q/ is the distribution axis 7
As the zero rotation angle θ increases, it decreases in proportion to it.

In this way, by rotating the cam ring 32, the capacity of the hydraulic motor changes.The rotation of the cam ring 32 is performed by slidingly displacing the piston 34 housed in the cylinder chamber 33. . That is, the switching valve 4
0 is at the switching position ←), both the oil chambers 35 and 38 are connected to the tank 42 and have equal pressure. For this purpose, the pistons 34 and 37 are displaced to the left in the figure by the spring 36,
The base end of the piston 37 is held at a position where it is in contact with the inner wall of the oil chamber 38. Therefore, the control pin 39 engaging the piston 34 causes the cam ring 32 to be in the minimum displacement position displaced by an angle θ from the maximum displacement position. Therefore, when the switching valve 40 is switched to the switching position (A), the oil chamber 38 is connected to the pump 41, the inside of the core oil chamber 38 becomes high pressure, and this pressure acts on the piston 37. On the other hand, the oil chamber 35 is located in the tank 4.
2, a pressure difference is generated between the core oil pipes 38 and 35. This pressure difference causes the piston 37 to resist the spring 36 and press the piston 37 to the right in the figure. As a result, the cam ring 32 together with the control pin 39 is rotated in the direction of increasing capacity, and its eccentric direction is located on the 8-in line in FIG. 3, and the capacity of the hydraulic motor is maximized.

In the above-described embodiments, the radial piston type hydraulic rotary machine according to the present invention is used together with a hydraulic motor, but it goes without saying that it may also be used as a hydraulic motor. Furthermore, although a cylinder piston device is used as the cam ring rotation mechanism for rotating the cam ring 32, the cam ring rotation mechanism can also be constructed using this rack-and-pinion mechanism or the like. Furthermore, although the distribution shaft 7 has been described as being separate from the rear casing 31B, the distribution shaft 7 is separate from the rear casing 31B.
It can also be configured integrally with

Furthermore, a hydraulic chamber is formed in the sliding portion between the sliding surface 32A of the cam ring 32 and the inner circumferential wall 31D of the cylindrical casing 31C, and the hydraulic pressure on the high pressure side of the hydraulic rotating machine is stored in this hydraulic chamber.
That is, in the case of a hydraulic motor, the supply pressure can be applied, and in the case of a hydraulic pump, it can be configured to apply the discharge pressure. In this case, the size of the hydraulic chamber is such that the cam ring 3
2, so that a separation force equal to or slightly smaller than that is applied. As a result, the capacity of the hydraulic rotating machine can be changed smoothly, and the leakage of pressure oil from the sliding parts can be minimized, thereby preventing the efficiency of the hydraulic rotating machine from decreasing. can.

[Brief explanation of the drawing]

Figures 1 and 2 show the prior art. Figure 1 is a longitudinal sectional view of a hydraulic rotating machine, Figure 2 is a sectional view in the direction of the Fig. 6 shows an embodiment of the present invention, Fig. 3 is a longitudinal sectional view of a hydraulic rotating machine, Fig. 4 is a sectional view in the direction of the ■−■ of the diagram
Cross-sectional view in the direction of the arrow, Figure 6 (a) 2←)? 'i is an explanatory view of the operation of the hydraulic rotary machine showing different operating states. 3... Rotor, 4... Cylinder, 5... Piston, 6... Shoe, 7... Distribution shaft, 31... Casing, 32... Cam ring, 32A... Sliding surface, 32
B...Cam surface, 33...Cylinder chamber, 34.37.
...Piston, 35°38...Oil chamber, 39...Control pin. Figure 3 IV. Δ -1 -51〇- Fig. 4 1'''v LV3'lC

Claims (1)

[Claims] a distribution shaft provided protruding within the casing; a rotor rotatably fitted into the distribution shaft within the casing; a plurality of cylinders bored radially in the rotor; a cam ring whose outer peripheral surface is coaxial with the distribution shaft and is slidably provided on the inner peripheral wall of the casing, and whose inner peripheral surface is eccentric with respect to the distribution shaft and serves as a cam surface for guiding the piston; ,
A radial piston type hydraulic rotating machine comprising a cam ring rotation mechanism that slides the cam ring along the inner circumferential wall of the casing.