JP2502265Y2 - Tilt angle control bolt for swash plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a tilt angle regulation mechanism that regulates the maximum value of displacement in a variable displacement swash plate type pump, a motor and the like.

(Prior Art) In a variable displacement swash plate type pump, the maximum value of the discharge amount is set by using a tilt angle regulating mechanism as shown in FIG. 5, for example.

In this figure, a swash plate 1 is accommodated in a body 4 so as to be tiltable around an O point, and its end portion is formed by a yoke spring 6 and a regulator piston (not shown) against a load acting with the operation of a pump. Supported to the left of.

The regulator piston changes the discharge amount according to the discharge pressure of the pump. For example, when the discharge pressure is low, the swash plate 1 is pressed so as to increase the tilt angle θ and tilted around the center O. .

On the other hand, the tilt angle regulation mechanism is composed of a bolt 5 screwed into the body 4 and a spool 3 supported by the bolt 5, and the tip of the spool 3 is located on the opposite side of the regulator piston or the yoke spring 6 from the swash plate 1. By contacting the end of the swash plate 1, the increase of the tilt angle θ of the swash plate 1 is restricted to a certain limit. Since the pump discharge amount increases with the tilt angle θ, the discharge amount when the swash plate 1 contacts the spool 3 becomes the maximum discharge amount of the pump.

The tilt angle restriction position can be arbitrarily changed by rotating the base end portion 5B of the bolt 5 projecting to the outside of the body 4. That is, when the base end portion 5B is rotated, the bolt 5 screwed into the body 4 is displaced in the axial direction by screw feeding, and the position of the spool 3 contacting the swash plate 1 is changed.

(Problem of the invention) However, in this operation, the tip 5A of the bolt 5 and the spool 3 slide in the rotational direction under the pressure of the yoke spring 6, so that if these operations are performed frequently, these sliding surfaces However, there was a problem that it was easily worn due to friction.

In order to prevent such wear of the member, the hardness of the sliding surface of the tip portion 5A and the spool 3 should be increased to smooth the surface, but the sliding surface of the spool 3 should be the bottom surface of the cylindrical recess 3A. Therefore, it was difficult to perform such processing.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent wear of a spool due to a rotational operation of a tilting angle regulating bolt.

(Means for Achieving the Problem) According to the present invention, the tilt angle of the swash plate is increased to a certain value or more by screwing it into the body of the swash plate type fluid machine and bringing the tip end into contact with the swash plate via the spool. To regulate
In a tilting angle regulating bolt of a swash plate that changes this regulating position by axial displacement according to a rotating operation, a collar that comes into contact with the spool and is rotatable relative to the bolt is attached to the bolt tip portion, The frictional resistance of the spool with respect to this collar was set to be larger than the frictional resistance of the tip of the bolt with respect to the collar.

(Operation) When the bolt is rotated, the bolt and collar, which have a relatively small frictional resistance, slide relative to each other to rotate, but the collar and the spool, which have a relatively large frictional resistance, do not slide together and are integrated together. Displace in the axial direction. Therefore, the collar and the spool do not slide, and the contact surfaces between them do not wear. On the other hand, since both the bolt and the collar have high hardness and are processed and heat-treated so as to make the surface smooth, wear does not occur even on their contact surfaces.

(Embodiment) FIGS. 1 to 4 show an embodiment of the present invention.

As shown in FIG. 1, a cylindrical collar 7 having the same diameter is rotatably attached to the tip portion 5A of the bolt 5 via a locking pin 8. The sliding surface between the collar 7 and the tip portion 5A of the bolt 5 has high hardness and is subjected to processing and heat treatment so that the surface is smooth in consideration of wear resistance. The configuration of the other parts is similar to that of the conventional example.

 Next, the operation will be described.

The bolt 5 supports the spool 3 via the collar 7 as shown in FIG. 2, and the spool 3 is moved forward or backward by a rotating operation to change the maximum tilt angle of the swash plate. In that case, pressure in the direction of the arrow acts on the spool 3 and the bolt 5 via the swash plate, but when the bolt 5 is rotated under this pressure, the collar 7 rotates to the spool 3 having a larger frictional resistance. Is regulated, and relatively rotates with the tip 5A of the bolt 5 having a small frictional resistance.

In other words, since the collar 7 and the spool 3 only contact but do not slide, there is no fear that these contact surfaces will wear. On the other hand, since the tip 5A of the relatively rotating bolt 5 and the sliding surface of the collar 7 are preliminarily processed to have a smooth surface and high hardness, the friction resistance of this sliding surface is small.
High wear resistance. Therefore, even if the bolt 5 is frequently rotated, each member is less likely to be worn and has sufficient durability.

Since the tip 5A of the bolt 5 and the collar 7 are both cylindrical, the surface can be easily processed.

FIG. 3 shows another embodiment of the present invention, in which the slide bearing 9 is fixed to the tip 5A of the bolt 5, and the slide bearing 9
The collar 7 is supported via. In this case, since the bolt 5 and the collar 7 do not come into direct contact, the tip of the bolt 5
Processing of 5A itself becomes unnecessary.

(Effects of the Invention) As described above, according to the present invention, a rotatable collar is attached to the tip of the tilting angle regulating bolt of the swash plate type fluid machine, and this collar supports the swash plate via the spool. At the same time, the frictional resistance of the spool for this collar was set to be larger than the frictional resistance of the bolt tip for the collar. While rotating relative to each other, the collar and the spool, which have a large frictional resistance, are integrally displaced in the axial direction without sliding.

Therefore, there is no fear of the spool being worn, and the durability of the tilt angle regulating mechanism can be improved with a simple structure.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential portion of a tilt angle regulating bolt showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of an essential portion of a tilt angle regulating bolt and a spool, and FIG. 3 is another embodiment. FIG. 4 is a vertical cross-sectional view of a main part of the tilt angle restricting bolt, and FIG. 4 is a vertical cross-sectional view of the tilt angle restricting bolt and the spool. Further, FIG. 5 is a sectional view of a main part of a swash plate type pump showing a conventional example. 3 ... Spool, 5 ... Bolt, 5A ... Tip, 7 ...
Color.

Claims (1)

(57) [Scope of utility model registration request] 1. A swash plate type fluid machine is screwed to a body thereof, and a tip end of the swash plate is brought into contact with the swash plate via a spool to prevent the tilt angle of the swash plate from becoming larger than a certain value.
In the tilt angle regulation bolt of the swash plate that changes the regulation position by axial displacement according to the rotation operation, a collar that is in contact with the spool and is free to rotate relative to the bolt is attached to the bolt tip portion, A tilt angle regulating bolt characterized in that the frictional resistance of the spool with respect to this collar is set to be larger than the frictional resistance of the tip portion of the bolt with respect to the collar.