JPH032714Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an axial piston machine, specifically a cylinder block having a large number of pistons, a swash plate having a contact surface portion with which the heads of the pistons come into contact; The present invention relates to an axial piston machine having a control pressure applying surface on one side in the length direction and an operating plunger for controlling the inclination angle of the swash plate.

(Prior Art) Conventionally, in an axial piston machine, a swath plate whose inclination angle is controlled by the operation of the operating plunger is used when the operating plunger does not operate, that is, when the control pressure is applied to the control pressure acting surface. If not, it is biased to maximum tilt angle.

As this biasing means, as shown in Japanese Patent Application Laid-Open No. 53-13204, a bias piston is disposed on the swashplate at a position symmetrical to the operation plunger, and high line pressure is applied to this piston, thereby Provisions are also made for pressing the plate to its maximum angle of inclination.

(Problems to be Solved by the Invention) When using the bias piston in a conventional axial piston machine, the bias piston and the cylinder for receiving the piston must be specially formed separately from the operating plunger. In addition, since the bias piston and cylinder need to be provided at symmetrical positions with respect to the operating plunger, the main body of the machine becomes large.

The object of the present invention is to provide a bias piston on the other longitudinal side of the operating plunger, which has a control pressure application surface on one longitudinal side, so as to bias the swath plate in the direction of the maximum inclination angle together with a spring. By doing so, the structure can be simplified and downsized.

(Means for Solving the Problems) The present invention includes a cylinder block 5 having a large number of pistons 5a, a swash plate 7 having a contact surface portion 7a with which the heads of the pistons 5a come into contact, and a swash plate 7 on one side in the length direction. In an axial piston machine comprising a control pressure acting surface 9a and an operating plunger 9 for controlling the inclination angle of the swash plate 7, the operating plunger 9 is disposed on one side of the swath plate 7 in the radial direction. An interlocking mechanism is provided between the swash plate 7 and the operating plunger 9 to transmit the operation of the operating plunger 9 to the swash plate 7,
A spring 22 for biasing the swash plate 7 in the maximum inclination direction and a bias piston 23 are provided on the other longitudinal side of the operating plunger 9, while a line pressure passage 26 is provided in the operating plunger 9.
A communication passage 24 is provided to communicate with the passage 24.
is characterized in that it communicates with the bias piston chambers 25, 25A.

(Function) The swash plate 7 is urged in the direction of the maximum inclination angle together with the spring 22 by the bias piston 23 provided on one longitudinal side of the operating plunger 9, which is disposed on one radial side of the swash plate 7. When the operation plunger 9 is operated, it is moved against the pressing force of the bias piston 23 and the spring 22, and the swash plate 7 is moved.
Since the piston is operated in the direction of the minimum inclination (neutral position), the structure can be simplified and made smaller while having the same function as the conventional one, and the introduction of line pressure to the bias piston chamber 25 is provided in the operation plunger 9. Since this is done through the communication passage 24, the transmission mechanism to the swash plate 7 can be easily supplied with oil.

(Example) The axial piston machine shown in Fig. 1 adopts a cradle-type swash plate support structure, and has a machine body 1 equipped with an end cap 1a, a front bearing 2 and a rear bearing 3. A cylinder block 5 having a large number of pistons 5a is supported on the main shaft 4 by spline connection, and the pistons 5a are mounted on one side, that is, the front side, of the cylinder block 5. A swash plate 7 is provided, which has a contact surface 7a with which the head of the swash plate 7 comes into contact via the shoe 6, and a cylindrical sliding surface 7b constituting a cradle-type support structure on the back side. is supported on the cylindrical receiving surface 8a of the holder 8 fixed to the machine main body 1 so that its inclination angle can be changed, while a pressure compensator valve (hereinafter referred to as a PC valve), for example, is installed radially outward of the swath plate 7. ), the operating plunger 9 and the swash plate 7 are interlocked via an interlocking mechanism to be described later, and the operation of the operating plunger 9 causes the swath plate 7 to move. The inclination angle is controlled, the discharge amount of the pump is adjusted, and the rotation speed of the motor is adjusted.

More specifically, the swath plate 7 and the holder 8 are configured as shown in FIGS. 2 and 3, and constitute a cradle-type support structure, and the holder 8 is configured as shown in FIGS. It is assembled into the mounting hole of the front side bearing 2 with a spigot and fixed with bolts 10, and the swash plate 7 is interposed between the holder 8 and the front side of the cylinder block 5. By the action of a spring 22 and a bias piston 23, which will be described later, the angle of inclination is biased to the maximum until the line pressure reaches the set pressure set by the PC valve.

That is, a control pressure applying surface 9a is provided on one side in the length direction of the operating plunger 9, and the swash plate 7 is urged in the direction of the maximum inclination angle via an interlocking mechanism to be described later on the other side. spring 22
and a bias piston 23 having a working surface 23a.
and the operating plunger 9 is provided with a communication passage 24 that communicates with the line pressure passage 26, and this passage 24 is communicated with the bias piston chamber 25 formed between the bias piston 23 and the operating plunger 9. The area of the bias piston 23 on the working surface 23a is set smaller than the area of the working surface 9a of the operating plunger 9.

However, if the PC valve does not operate, i.e.
When the line pressure is lower than the set pressure set by the PC valve, the control pressure application surface 9a of the operating plunger 9 is open to the tank, while the line pressure is guided to the bias piston chamber 25. Therefore, due to this pressure, the operating plunger 9 is pressed to the left in FIG. 1 together with the spring 22, and the swash plate 7 is pressed in the direction of the maximum inclination angle.

In the embodiment shown in FIG. 1, the operating plunger 9 is movably housed in a valve block 14 provided separately from the machine body 1, and this valve block 14 is mounted on one side of the machine body 1. That is, it is arranged on one side in the radial direction of the swash plate 7 and fixed to the machine body 1, and openings 14a and 1 are provided in the valve block 14 and the machine body 1, respectively.
b, and an interlocking mechanism between the operating plunger 9 and the swash plate 7 is constructed as follows. That is, a driving body 20 that protrudes into the machine body 1 through the openings 14a and 1b is provided on the operating plunger 9, and is fixed mainly by screw means, and a sphere 20a is mainly integrated at the tip of the driving body 20. The swash plate 7 is provided with a receiving portion 7d for the driven member 21, and the driven member 21 is slidably connected to the spherical body 20a. It is composed by allowing free intervention.

Furthermore, in the interlocking mechanism configured as above,
The driving body 20 and the driven body 21 communicate with the communication passage 24 provided in the operating plunger 9,
Oil passages 20b and 21a are provided for lubricating the sliding surface of the receiving portion 7d of the driven body 21, and the receiving portion of the driven body 21 is oiled by lubricating the sliding surface from the oil passage 21a. 7d can be smoothly slid, and the swash plate 7 can also be tilted smoothly.

Moreover, on the rear side of the cylinder block 5,
A valve plate 12 having a high pressure port 12a and a low pressure port 12b is arranged, the rear end surface of the cylinder block 5 is in contact with the valve plate 12, and the piston 5a provided in the cylinder block 5 is in contact with the valve plate 12. is housed in the cylinder block 5 so that it can freely reciprocate, and a spherical shoe 6 is attached to the head of each piston 5a so that it can swing freely. 13,
It is brought into contact with the contact surface portion 7a of the swash plate 7.

In addition, in FIG. 1, 27 communicates with the PC valve,
This is a control pressure passage that guides control pressure fluid to the control pressure application surface 9a of the operating plunger 9 by the operation of the PC valve.

Further, in FIG. 2, reference numeral 7c denotes an oil supply passage provided in communication between the contact surface portion 7a and the sliding surface 7b of the swash plate 7,
Oil supply hole 6a (first
(Fig.) is designed to be refueled intermittently.
In addition, in FIG. 3, reference numeral 8b denotes an oil sump groove communicating with the oil supply path 7c, and of the receiving surface 8a of the holder 8, the right receiving surface 8a in FIG. The swash plate 7 is smoothly tilted relative to the holder 8 by supplying oil from the oil reservoir groove 8b.

In the axial piston machine configured as described above, when the main shaft 4 is driven and the cylinder block 5 is rotated, each piston 5a slides along the contact surface portion 7a of the swash plate 7 and reciprocates. By repeating this, a pumping action can be performed.

When the pump is performing the pump action as described above, the line pressure, that is, the pump discharge pressure is
Until the set pressure set by the valve is reached, the swash plate 7 reaches its maximum inclination angle due to the pressing force of the spring 22 acting on the operating plunger 9 and the pressing force due to the line pressure acting on the bias piston 23. The axial piston machine, which is held and acts as a pump, will discharge at maximum flow rate.

Therefore, the swash plate 7 is biased to the maximum inclination angle not only by the pressing force of the spring 22 but also by the pressing force generated by the bias piston 23. Therefore, the force of the spring 22 is exerted only by the spring. Moreover, since the bias piston 23 is provided on the operating plunger 9, the structure can be made simpler and smaller than when the operating plunger 9 is provided at a symmetrical position. It is.

Furthermore, since the operating plunger 9 is provided with the communication passage 24 to the bias piston chamber 25, the sliding parts of the interlocking mechanism can be easily lubricated.

In the embodiment shown in FIG. 1, the bias piston 23 has a spherical tip end surface protruding from the operating plunger 9, and is threaded onto the wall surface of the valve block 14 in which the operating plunger 9 is slidably installed. The contact body 15 is brought into contact with the attached contact body 15 so that the contact position can be changed, and a spring receiver 28 is locked to the tip of the bias piston 23.
The other end of the spring 22, whose one end is locked to the operation plunger 9, is received. The reason why the tip surface of the bias piston 23 is made spherical and the spring 22 is received on the tip surface is that the bias piston 23 is fixed to the valve block 14, and the operation is easier. This is to make it possible to absorb errors when assembling the plunger 9 to the valve block 14 without requiring high dimensional accuracy.

In the embodiment shown in FIG. 1, the bias piston chamber 25 is provided in the operating plunger 9, and the bias piston 23 is internally movable relative to the operating plunger 9. Similarly, the bias piston 23 may be provided with a bias piston chamber 25A, and the bias piston may be fitted around the outer periphery of the operating plunger 9 so as to be movable relative to the plunger 9.

Further, the driving body 20 constituting the interlocking mechanism
is connected to the operation plunger 9 by screw means, but it may be formed integrally with the operation plunger 9, or if it is formed separately, it may be formed so as to hold and fix the outer periphery of the operation plunger 9. In any case,
The communication passage 24 provided in the operation plunger 9
communicates with the bias piston chambers 25, 25A via a protruding portion of the drive body 20, and when the drive body 20 is coupled by screw means, the communication passage is connected to the screwing position of the drive body 20. 24
An annular groove 20c is formed at a position corresponding to the oil passage 20b provided in the drive body 20.
is communicated with this annular groove 20c.

Further, in the embodiment described above, the swash plate 7 is supported by a cradle system, but other structures in which the swash plate 7 is supported using a trunnion shaft may be similarly applied. Further, the connection structure between the driving body 20 and the driven body 21 is preferably a ball joint structure, but other pin connection structures may be used.

Furthermore, although the above description has been made regarding a pump, it can also be used as a motor.

(Effects of the invention) The present invention provides an operating plunger 9 having a control pressure acting surface 9a on one side in the length direction.
The operating plunger 9 is arranged on one side in the radial direction of the operating plunger 9, and the operating plunger 9 is interlocked with the swash plate 7 via an interlocking mechanism, and the operating plunger 9 is disposed on the other longitudinal side of the operating plunger 9 so that the swash plate 7 is tilted to the maximum inclination. An angularly biasing spring 22 and a bias piston 23 are provided, and the operating plunger 9 is provided with a communication passage 24 communicating with a line pressure passage 26, which passage 24 is connected to the bias piston chambers 25, 2.
5A, the structure is simpler and more compact than a conventional axial piston machine in which an operating plunger and a bias piston are placed opposite each other at both ends of a swash plate.

Furthermore, since the operating plunger 9 is provided with a communication passage 24 that communicates the bias piston chambers 25, 25A with the line pressure passage 26, when the interlocking mechanism that interlocks the movement of the operating plunger 9 with the swash plate 7 is supplied with oil. , said communication passage 2
4, the oil supply structure can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a perspective view of the swath plate, Fig. 3 is a perspective view of the holder, and Fig. 4 is a diagram showing only the main parts of another embodiment. FIG. 5...Cylinder block, 5a...Piston,
7...Swatshi plate, 7a...Contact surface part,
9... Operation plunger, 9a... Control pressure application surface,
22...Spring, 23...Bias piston, 24
...Communication passage, 25, 25A...Bias piston chamber.

Claims (1)

[Scope of utility model registration request] Cylinder block 5 with many pistons 5a
and a contact surface portion 7 with which the head of the piston 5a comes into contact.
an axial piston machine comprising a swash plate 7 having a diameter of 1.a, and an operating plunger 9 having a control pressure acting surface 9a on one side in the longitudinal direction and controlling the inclination angle of the swash plate 7; 9 is disposed on one side of the swash plate 7 in the radial direction, and an interlocking mechanism is provided between the swash plate 7 and the operating plunger 9 for transmitting the operation of the operating plunger 9 to the swash plate 7. In addition, a spring 22 for biasing the swash plate 7 in the maximum inclination direction and a bias piston 23 are provided on the other longitudinal side of the operating plunger 9, while a line pressure passage 26 is provided in the operating plunger 9. An axial piston machine characterized in that a communication passage 24 is provided which communicates with the bias piston chambers 25 and 25A.