JPH0510509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable swash plate type hydraulic motor, and more particularly to a variable swash plate type hydraulic motor that enables variable control of two high and low speeds.

2. Description of the Related Art Variable swash plate type hydraulic motors have conventionally been used in bulldozers, shovel dozers, and other devices that require two-speed running, high speed and low speed. The mechanism for changing the displacement of this variable swash plate type hydraulic motor requires a trunnion, etc. on the swash plate, and a bearing, etc. on the trunnion part to facilitate tilting.As a result, the hydraulic motor becomes larger, and is used in bulldozers. There was an inconvenience that it required a large space when mounted on a shovel dozer. Furthermore, it is structurally complex, which is also a factor in increasing costs.

Further, as this type of variable swash plate type hydraulic motor, for example, Japanese Patent Publication No. 39-6476, Japanese Patent Publication No. 41-16467
Publication No. 51-129905, Utility Model Publication No. 1982-129905
Publication No. 78857, United States Patent No. 3070031 =
Japanese Patent Publication No. 39-10784 British Patent No. 1055286, US Patent No. 3935796 = Japanese Patent Application Publication No. 139404-1984, and Japanese Patent Application Publication No. 112205-1987 = Japanese Patent Publication No. 1987-112205
One disclosed in Publication No. 47230 and the like is known.
However, in all of these, the structure of the tilting angle control mechanism of the swash plate is complicated, and the workability and assemblability are poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a new variable swash plate type hydraulic motor that is small and lightweight, can be extremely easily mounted on a vehicle such as a bulldozer, and can reduce costs.

To achieve this object, the present invention includes a casing, a rotating shaft rotatably supported by the casing, a cylinder block connected to the rotating shaft, a plunger inserted into the cylinder block, and a rotating shaft rotatably supported by the casing. A hydraulic motor comprising a swash plate that is fitted to an end of a plunger and is in contact with a shoe, and a tilt angle control member is provided to face the swash plate and tilt the swash plate, and the swash plate is , comprising a sliding surface portion with which the shoe contacts, and a first sheet surface and a second sheet surface formed on the opposite side of the sliding surface portion and having different angles that selectively contact the inner wall of the casing. , the swash plate can be tilted by the tilt angle control member using the intersection line of the first seat surface and the second seat surface as a fulcrum, and further there is a gap between the swash plate and the inner wall of the casing The present invention is characterized in that a positioning member for the swash plate is provided on the intersection line.

The present invention will be explained below based on the illustrated preferred embodiments.

FIG. 1 shows a circuit diagram when used as a two-speed hydraulic motor A according to the present invention.
When engine B operates, oil from oil pump C reaches hydraulic motor A via outward path D, and after driving hydraulic motor A, the oil returns to oil pump C via return path E. This hydraulic motor A has a casing 1 as shown in FIG.
, rotating shaft 2, cylinder block 3, and swash plate 4
and a plate 5.

The cylinder block 3, swash plate 4, and plate 5 are provided inside the casing 1, and the casing 1 itself has crescent-shaped ports 5a and 5b (not shown) bored in the plate 5. A supply oil passage 11, a discharge oil passage 12, and an auxiliary oil passage 13 are bored to connect, and the casing 1 is provided with an auxiliary cylinder 14 that communicates with the auxiliary oil passage 13. A pressing member P is fitted into the auxiliary cylinder 14 and is slidable by hydraulic pressure applied through the auxiliary oil passage 13 . This pressing member P is used as a tilting angle control member for tilting the swash plate 4. This pressing member P consists of an auxiliary plunger 15 and an auxiliary shoe 16, and the auxiliary shoe 16 is rotated at the tip of the auxiliary plunger 15. It is fitted so that it can move freely. In addition, the auxiliary oil passage 13 includes a separate route from the oil pump C (see Fig. 1).
Oil is directed through a control device (not shown).

On the other hand, a rotating shaft 2 connected to the cylinder block 3 by a spline or the like is rotatably supported in the center of the casing 1 via bearings 20 and 21, and is sealed by a sealing member 22.

The cylinder block 3 is adapted to rotate within the inner cavity 10. Note that a joint hole 23 is formed at one end of the rotary shaft 2 to which a rotary shaft (not shown) of, for example, a speed reducer is connected. It goes without saying that the method of connecting the cylinder block 3 to the rotating shaft 2 may be arbitrarily selected other than the spline connection described above.

The cylinder block 3 is provided with a plurality of cylinder holes 30. This cylinder hole 30
A plunger 31 is inserted into the interior through an opening at one end, and a shoe 32 is inserted at the tip of the plunger 31.
is rotatably fitted. The distal end surface of this shoe 32 is in contact with the sliding surface portion 42 of the swash plate 4. The cylinder hole 30 has a port 33 that communicates with the port hole 5a bored in the plate 5. This port 33 is configured to selectively communicate with the supply oil passage 11 or the discharge oil passage 12 in accordance with the rotation of the cylinder block 3. Further, this cylinder block 3 is provided with a pressing device that always presses the cylinder block 3 against the plate 5 and the shoe 32 against the swash plate 4 at all times. That is, a space of an appropriate size is formed near the center of the cylinder block 3 and adjacent to the rotating shaft 2, and a stopper 34 is provided protruding from the cylinder block 3 in this space, and one piece is attached to the stopper 34. 35a
The piece 35a holds one end of the spring 36, and the other end of the spring 36 is held on the other piece 35b, so that the piece 35a holds one end of the spring 36.
5b, a rod 37 passing through the cylinder block 3
A cam 38 is brought into contact with the tip of the rod 37, and a stopper piece 39 attached to the shoe 32 is brought into contact with the cam surface of the cam 38. That is, this pressing device presses the cylinder block 3 against the plate 5 by the repulsive force of the spring 36, and also presses the cylinder block 3 against the plate 5.
is pressed against the swash plate 4 by a stopper piece 39.

The swash plate 4 is formed to have a donut-shaped planar shape as a whole, as shown in FIG. 3A, and a wedge-shaped side surface shape as a whole, as shown in FIG. 3B. has been done. Swash plate 4
The adjacent surface on the casing 1 side provided on the opposite side to the sliding surface portion 42 is composed of a first seat surface 40 and a second seat surface 41 having different angles. The inner wall 1, which is one plane of the casing 1, with one of the surfaces 41 as a stopper.
By making contact with a, the angle of the swash plate 4 can be changed in two ways, and variable control can be performed in two speeds corresponding to the angle of the swash plate 4. That is, when the swash plate angle is changed, the plunger stroke changes, which changes the amount of oil suction, and as the shaft speed changes, the output also changes. The sliding surface portion 42 on the shoe 32 side is formed into an inclined surface with an angle larger than the inclination angle of the second seat surface 41, and allows the shoe 32 to slide. The swash plate 4 tilts around a line O where the first seat surface 40 and the second seat surface 41 intersect (hereinafter referred to as the intersection line O) as a fulcrum. Further, a ball hole 43 centered on the intersection line O between the first seat surface 40 and the second seat surface 41 is formed, and a position corresponding to this ball hole 43 is formed. A ball 44 serving as a positioning member is held between a ball hole (not shown) formed in the inner wall 1a of the casing 1 with a slight gap therebetween,
The swash plate 4 is positioned by the balls 44. Therefore, when the auxiliary shoe 16 adjacent to the upper end of the first seat surface 40 moves to the left in FIG. The plate 4 is tilted at a constant angle using the intersection line O as a fulcrum. At this time, since the ball 44, which is a positioning member, is arranged on the intersection line O, the position of the ball 44 does not shift; on the contrary, the position of the swash plate 4, which is positioned by this ball 44, and the intersection line O are at a constant position. As a result, the inner wall 1a of the casing 1 at the intersection line O
The contact position is not right. Auxiliary cylinder 1
When no hydraulic pressure is applied to the auxiliary plunger 15 in the swash plate 4, the swash plate 4 always remains on its first seat surface 40.
Inner wall 1a of casing 1 using only as a stopper
(See Figure 4 A).

However, pressurized oil is fed into the auxiliary cylinder 14 from the auxiliary oil passage 13 and the auxiliary plunger 15
When the swash plate 4 moves to the left in FIG. The second seat surface 41 of the casing 1 is supported in contact with the inner wall 1a of the casing 1 as a stopper (see FIG. 4B). At this time, the auxiliary shoe 16
The pressing force f acting on the swash plate 4 and the pressing force F acting on the swash plate 4
If the following equation holds true between , the swash plate 4 maintains a stable contact state with the inner wall 1a of the casing 1 with its second seat surface 41. That is, f>b/
a×F and f<(b+l)/(a+l)×F. When f=0, that is, the swash plate 4 comes into stable contact with the inner wall 1a of the casing 1 with its first seat surface 40, because the action on the swash plate 4 as shown in FIG. This is because the pressing force F acts on a position eccentric to the upper end side by b' in the figure from the center of the intersection line O. It goes without saying that the swash plate 4 is formed with an opening 45 through which the rotating shaft 2 can be inserted, and also to avoid contact with the bearing 21 due to the rotation of the swash plate 4. A stopper piece 39 attached to the groove 46 and the shoe 32
Considerations have been made, such as forming a notch 47 to avoid contact between the two (see Figure 3 A and B).

As the positioning member, a hemispherical protrusion or a cylindrical or semi-cylindrical member is protruded at a position corresponding to the ball hole 43, and a corresponding receiving part is formed on the inner wall 1a of the adjacent casing 1. The positioning member may be configured to allow rotation.

The hydraulic motor A according to the embodiment of the present invention configured as described above operates as follows.

Auxiliary plunger 15 interposed on the back of swash plate 4
When there is no pressure, the cylinder block 3 is pressed against the plate 5, and the shoe 32 is pressed against the swash plate 4.
Since the plate 5 and the cylinder block 3 are pressed against each other, there is no possibility that oil will leak from adjacent locations such as between the plate 5 and the cylinder block 3, or that the cylinder block 3 will not be able to rotate due to this. If the cylinder block 3 is supplied inside, the cylinder block 3 will immediately rotate.

Oil is fed into the cylinder hole 30 and the plunger 31 slides, whereby the oil in the cylinder hole 30 is sequentially supplied and discharged. That is, when the cylinder block 3 is rotated in either direction, the plunger 31 compresses and enters into the cylinder hole 30, and the port 33 communicates with the crescent-shaped hole 5a formed in the plate 5, so that the cylinder The oil in the hole 30 is drained. On the other hand, when the plunger 31 extends, the port 5b at the rear of the cylinder block 3 and the port 33 communicate with each other, and oil begins to enter the cylinder hole 30, and these operations are selectively repeated to form a plurality of ports. Cylinder hole 30
By sliding the plunger 31 inside, the cylinder block 3 rotates, and the rotating shaft 2 connected thereto is rotationally driven. Therefore, by canceling the supply of oil, the rotational drive of the rotating shaft 2 can be stopped. As described above, the shoe 32 is always pressed against the swash plate 4 even when oil is not supplied.

The above operation is the same whether the swash plate 4 is in either of the cases shown in FIG. 4A and 4B. However, in the case of FIG. 4A, that is, when the first seat surface 40 of the swash plate 4 is supported in surface contact with the inner wall 1a of the casing 1, in the case of FIG. 4B, that is, the swash plate The rotation of the rotating shaft 2 is only slower than that in the case where the second seat surface 41 of the rotary shaft 2 is supported in surface contact with the inner wall 1a of the casing 1.
The tilting operation of the swash plate 4 has been described above, but the auxiliary plunger 15 and the auxiliary shovel 16
is not always pressed against the first seat surface 40 of the swash plate 4. When oil is not supplied into the auxiliary cylinder 14, the first seat surface 40 of the swash plate 4 is in surface contact exclusively with the inner wall 1a of the casing 1, so that no thrust is applied to the auxiliary plunger 15 at this stage. is not required. Further, when the inside of the auxiliary cylinder 14 is supplied with oil from the auxiliary oil passage 13 and becomes pressurized, the second seat surface 4 of the swash plate 4
1 is in surface contact with the inner wall 1a of the casing 1 and stabilized. Further, the thrust of the auxiliary plunger 15 does not need to be large. The thrust required for the auxiliary plunger 15 is sufficient as long as it satisfies the above-mentioned formula.

The above configuration and operation are an embodiment of the present invention as a hydraulic motor, but it goes without saying that when the present invention is used as an embodiment of a hydraulic pump, it is sufficient to rotate the rotary shaft 2 as a drive shaft. At that time, high-speed and low-speed discharge can be performed freely.

As described above, the present invention has the following effects.

It is possible to obtain a hydraulic motor that can freely change to two speeds, high speed or low speed. In addition, a first seat surface and a second seat surface having different angles are provided on the opposite side of the sliding surface of the swash plate, and the tilting is performed using the intersection line of the first seat surface and the second seat surface as a fulcrum. Since the swash plate is simply tilted using the angle control member, the structure is simple, and there is no need for conventional complicated transmission mechanisms such as trunnions or bearings, making it possible to reduce the size and weight of vehicles such as bulldozers. It is extremely easy to install and can reduce costs.

Since the swash plate tilts around the intersection line, the entire surface of either the first sheet surface or the second sheet surface on the back of the swash plate tightly contacts the inner wall of the casing, so the swash plate itself is stabilized. . Moreover, since the entire surface of the first seat surface or the second seat surface is in contact with each other, the contact area with the inner wall of the casing can be increased, and the reaction force from the plunger is received over the entire surface, so that the contact pressure is reduced. This also improves the durability of the swash plate and casing. Further, when installing and using the device, not only does it not require a large volume, but also the installation and preparation of complicated operating devices are not required, and it has the advantage that it can be used with simple operations.

Since the positioning member is placed between the swash plate and the casing and on the intersecting line, the position of the intersecting line is always regulated to a constant position by the positioning member, and as a result, even when the swash plate is tilted, the intersecting line is not relative to the inner wall of the casing. The position does not change, and the swash plate does not move vertically or horizontally.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a variable hydraulic motor according to the present invention, Fig. 2 is a vertical sectional view showing the hydraulic motor according to the present embodiment, Fig. 3A is a front view of the swash plate, and Fig. 3B is an oblique view. A side view of the plate, FIG. 4A and FIG. 4B are side views showing the operating state of the swash plate. DESCRIPTION OF SYMBOLS 1... Casing, 1a... Inner wall, 2... Rotating shaft, 3... Cylinder block, 4... Swash plate, 5...
... plate, 13 ... auxiliary oil passage, 14 ... auxiliary cylinder, 15 ... auxiliary plunger, 16 ... auxiliary shoe, 31 ... plunger, 32 ... shoe,
40...First seat surface, 41...Second seat surface, 42...Sliding surface portion, 44...Positioning member (ball), O...Intersection line, P...Tilt angle control member (pressing Element).

Claims (1)

[Claims] 1. A casing 1, a rotating shaft 2 rotatably supported by this casing, a cylinder block 3 connected to this rotating shaft, a plunger 31 inserted into this cylinder block, and this plunger. The swash plate 4 is in contact with the shoe 32 fitted to the end of the swash plate 4.
A hydraulic motor comprising: a tilting angle control member P facing the swash plate for tilting the swash plate, the swash plate having a sliding surface portion 4 with which the shoe contacts
2, and a first seat surface 40 and a second seat surface 41 that are formed on the opposite side of the sliding surface portion and selectively abut against the inner wall 1a of the casing and have different angles; The tilting angle control member allows the tilt angle control member to rotate about the intersection line O between the first seat surface and the second seat surface as a fulcrum, and furthermore, between the swash plate and the inner wall of the casing, the intersection line Positioning member 4 of the swash plate placed in
A variable swash plate type hydraulic motor characterized in that a variable swash plate type hydraulic motor is provided.