JPS6221995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-driven double-acting hydraulic pump suitable for raising and lowering an automobile repair lift.

The air drive device in a conventional air-driven double-acting hydraulic pump has a signal pressure outlet for switching the air valve installed in the middle of the side wall of the driving piston cylinder, and the outlet and the air valve are connected by a conduit. It was a lot. However, in this type of device, (1) If the signal pressure outlet is provided in the drive cylinder, the conduit must be attached by screws or welding, so the cylinder wall must be thick, and the welding In some cases, deformation of the cylinder is likely to occur.

(2) In general, as the length of the conduit becomes longer, signal delays may occur, causing malfunctions, and it may be difficult to drain oil and water that has accumulated in the conduit, resulting in malfunction of the air valve. .

(3) Since piston rings are usually made of soft materials such as rubber or plastic, they can sometimes be damaged by the outlet, and replacing them requires labor and cost.

There were other problems.

On the other hand, as an air drive device that eliminates the above-mentioned drawbacks, the air valve and one chamber of the drive cylinder are connected through a drive air supply/exhaust port.
There is a double-acting type in which the air valve and the other chamber are connected by a supply/exhaust pipe that passes through the driving piston. However, even in this type of device, since the supply and exhaust pipes pass through the drive piston, (4) the piston cannot rotate, so an uneven load is applied to the piston, which tends to cause uneven wear on the piston. Therefore, the wall thickness of the piston must be increased.

(5) A high degree of processing precision is required to install the through-hole supply and exhaust pipes.

(6) The air drive device must be designed to be located between the air valve and the hydraulic pump.

There were other problems.

In addition, as shown in Japanese Patent Publication No. 48-29882 and No. 50-21161, an air valve for an air drive device uses differential pressure between two pistons with different areas, which are placed on the same axis at a predetermined distance. Various things are used. However, in these air valves, in order to pressurize or depressurize the larger piston, a pilot valve biased to one side by a compression spring is installed in a part of the air valve passage, and the stem or ball of the pilot valve is driven. This is done by pushing with a rod-shaped body provided on the drive piston or an extension of the drive piston, so when the drive piston becomes high speed, the repulsive force of the compression spring does not follow the speed of the drive piston, There was a problem with not being able to drive at high speeds.

Furthermore, if the hydraulic pump is a plunger type, the cross-sectional area of the plunger must be extremely small in order to obtain high oil pressure with an air drive device with limited horsepower, making it difficult to incorporate a valve mechanism into the plunger. There were times when it happened.

The present invention provides a hollow hole in the piston rod of an air drive device, makes it part of the air supply/exhaust passage to one cylinder chamber, and provides a signal pressure outlet in the middle of the air supply/exhaust passage. The air valve is controlled by a guide, and the hydraulic pump has a piston part that slides inside the bore in a part of the plunger, and a cross-sectional area from the plunger on the opposite side of the plunger with the piston part as a boundary. A new suction oil amount limiting rod with a small diameter is newly installed, and when the plunger moves in one direction, the pressurizing cross-sectional area is the difference in cross-sectional area between the plunger and the suction oil amount limiting rod, and conversely, when the plunger moves in the other direction. The pressurized cross-sectional area during movement is the difference between the cross-sectional areas of the piston and the plunger, and by making both pressurizing cross-sectional areas equal, the load on the air drive device and the amount of oil discharged can be made uniform, and the diameter of the plunger can be made uniform. This made it possible to increase the size.

The present invention will be explained below with reference to Examples. In this embodiment, when left and right and top and bottom are used to indicate positional relationships and directions, they refer to the left and right and top and bottom positions in the attached drawings.

First, the air drive device will be explained. A driving piston 12 is fitted inside the driving cylinder 11, and the rod 1 of the driving piston 12 is inserted into the driving cylinder 11.
3 has a hole 14 extending in the axial direction. The left end of this hole 14 is open and communicates with the left cylinder chamber 15.
It serves as a supply and exhaust passage for driving air sent to the
The right end is a dead end. The rod 13 has a diameter larger than the part where the hole 14 ends, forming a piston-shaped spool valve control guide 16. This spool valve control guide 16 slides in a guide cylinder 17 surrounding the rod 13 and forms an air passage 18 between it and the rod 13. The left end of the air passage 18 is separated from the cylinder chamber 20 on the right side of the driving cylinder 11 by a separation wall 19 that seals the rod 13, and the air passage chamber 2 is formed in the wall 21.
It leads to 2. On the other hand, the right end of the air passage 18 communicates with a hole 14 in the rod 13 via a hole 23 made in the wall of the rod 13. Between the right cylinder chamber 20 and the air passage chamber 22 is a separation wall 2 fixed to the wall 21 with bolts 24.
5 is present to seal the air passage chamber 22 and to fix the separation wall 19 to the wall 21.

A signal pressure outlet hole 26 is provided approximately in the center of the guide cylinder 17, and a small diameter signal pressure outlet hole 27 is provided on the right side thereof. The distance between the signal pressure extraction hole 26 and the discharge hole 27 is greater than the width of the spool valve control guide 16 in the axial direction.

Now, in FIGS. 3 and 4, the spool valve is composed of a spool 30 having a pair of opposing holes 28 and 29 formed in each end surface, and a sleeve 31 on which the spool 30 slides. . The cross-sectional area of the hole 28 is larger than the cross-sectional area of the hole 29, and in this embodiment, it is approximately twice the cross-sectional area of the hole 29, and one end thereof is a dead end, and a first support is provided inside. The cylinder 32 is fitted from the other end side. This first support cylinder 32 is fixed to a seal plate 33, and has a hole 34 penetrated in the axial direction at its center. Moreover, the hole 34 is connected to the signal pressure extraction hole 2 through a groove 35 provided in the seal plate 33.
6, so that signal pressure air can be supplied and exhausted (Fig. 6). One hole 2
9 is open at both ends, and a second support cylinder 37 fixed to the mounting member 36 is fitted into one end, while the other end is open in the axial direction of the spool 30. The hole 39 is opened at a right angle, and both ends thereof communicate with a hole 39 opened between the protrusion 38 of the spool 30. Further, the second support cylinder 37 is provided with a hole 40 passing through it in the axial direction, and an air supply pipe 41 is connected thereto.

A plurality of holes 42, 43 are formed in two stages, upper and lower, along the circumference in the longitudinal center of the sleeve 31, and these holes 42, 43 are respectively provided with grooves 44, 43 formed along the outer periphery of the sleeve 31. 45, respectively. The openings of the grooves 44 and 45 are closed by the wall 21 to form an annular air passage, but a part of the grooves 44 and 45 are closed by the two first air supply and exhaust holes formed in the wall 21 in two stages, upper and lower. 46 and a second air supply/exhaust hole 47 . The first supply/exhaust hole 46 communicates with the air passage chamber 22, and the second supply/exhaust hole 47 passes through the separation wall 25 and communicates with the cylinder chamber 20 on the right side of the drive cylinder 11.

Further, two exhaust holes 48 and 49 are formed near both ends of the sleeve 31, and these exhaust holes 48 and 49 are connected to the silencing chamber 5.
It leads to 0,51. (Fig. 4) Next, the hydraulic pump will be explained. 1st again
In FIG. 2, the spool valve control guide 16
A plunger 52 extending in the axial direction is integrally provided in the plunger 52, and a seal wall 53 seals the periphery of the plunger 52. The seal wall 53 is attached to the wall 2 by bolts 56 to the mounting plate 55 to which the cylinder block 54 is fixed.
1, and its right side surface forms part of the discharge path.

The plunger 52 extending into the bore 57 has a piston portion 58 whose right end portion slides on the inner surface of the bore.
A first check valve 59 is provided inside. This check valve 5
9 communicates with a discharge side gap 61 through a hole 60, and further communicates with a suction side gap 63 through a hole 62.

A suction port 64 communicating with the suction side gap 63 is provided above the tip of the bore 57, and a second check valve 66 is provided between the suction port 64 and the hydraulic pipe 65. (Fig. 5) The piston portion 58 of the plunger 52 has a suction oil amount limiting rod 67 that extends in the axial direction of the plunger 52 and has a smaller cross-sectional area than the plunger 52.
is installed. This suction oil amount limiting rod 6
7 projects outward from the right end of the bore 57 and limits the amount of oil sucked into the bore 57. Therefore, the difference in cross-sectional area between the piston part 58 and the suction oil amount limiting rod 67 is twice the difference in cross-sectional area between the piston part 58 and the plunger 52, so that no matter which direction the plunger 52 moves, The cross-sectional area of the applied pressure remains constant.

A discharge passage 68 communicating with the discharge side gap 61 and a discharge passage 70 communicating with the discharge port 69 are provided inside the cylinder block 54, and both discharge passages 6
8 and 70 are connected via a third check valve 71.

In the air-driven double-acting hydraulic pump configured as described above, when compressed air is supplied from the air supply pipe 41 when the spool 30 of the air valve is in the position shown in FIG. 42, enters the first supply/exhaust hole 46 from the groove 44,
It reaches the left cylinder chamber 15 via the air passage 18, holes 23 and 14, and moves the driving piston 12 to the right. When the driving piston 12 moves to the right and the left side of the spool valve control guide 16 passes through the signal pressure outlet hole 26, pulse air flows from the signal pressure outlet hole 26 through the groove 35 and the hole 34 to the hole 2.
8. Here, since the cross section of the hole 28 is larger than the cross section of the hole 29, the differential pressure causes the spool 30 to be pushed downward in FIG. 3 and moved to the position shown in FIG. 4.

On the other hand, while the driving piston 12 is moving to the right, the right cylinder chamber 20 is exhausted through the second air supply/exhaust hole 47. That is, since the spool 30 is in the position shown in FIG. 3, the second supply/exhaust hole 47 communicates with the exhaust hole 49 through the groove 45, the hole 43, and the inside of the sleeve 31, and is exhausted.

By the way, when the spool 30 moves to the position shown in FIG. 4, the supply to the left cylinder chamber 15 and the right cylinder chamber 20 is reversed, so the drive piston 12 begins to move to the left, and the spool valve control guide 16 also closes the signal pressure extraction hole 26. As a result, the air pressure in the hole 28 is maintained until the right end of the spool valve control guide 16 comes out of a part of the signal pressure extraction hole 26, and the spool 30 does not move.

However, when the spool valve control guide 16 comes off from a part of the signal pressure outlet hole 26, the signal pressure outlet hole 26 and the signal pressure discharge hole 27 communicate with each other, so the hole 28
The air inside is discharged, and the spool 30 is moved by the air pressure applied to the hole 29, returning to the state shown in FIG. When the spool 30 returns, the signal pressure discharge hole 27 is narrowed and the spool valve control guide 16 moves to the left at high speed, so the space on the right side of the spool valve control guide 16 becomes negative pressure. The air in the hole 28 is expelled at high speed in cooperation with the pressure from the hole 29.

On the other hand, while the driving piston 12 is moving to the left, the first supply/exhaust hole 46 communicates with the exhaust hole 48 through the groove 44, the hole 42, and the inside of the sleeve 31, so that the air in the left cylinder chamber 15 is It is discharged.

By the way, as the air drive device reciprocates by repeating the above-described cycle, the hydraulic pump moves as follows. That is, when the plunger 52 moves to the left, the third check valve 71 opens and the oil existing in the discharge side gap 61 formed by the plunger 52 and the bore 57 is discharged, but at the same time, the second check valve 66 opens. When opened, twice the amount of oil discharged enters the suction side gap 6, which is composed of the suction oil amount limiting rod 67 and the bore 57.
Inhaled within 3 days. When the plunger 52 reaches the leftmost position (Fig. 2), the second
and third check valves 66 and 71 are closed.

On the other hand, when the plunger 52 begins to move to the right,
The first check valve 59 opens and the suction side gap 6
The oil in 3 is sent to the discharge side gap 61, and at the same time, the third check valve 71 is also opened and the oil is discharged.
That is, when the plunger begins to move to the right, the first and third check valves 59 and 71 open almost simultaneously, forming a discharge path from the suction side gap 63 through the discharge side gap 61 to the discharge port 69, The plunger 52 is held until it stops. When the plunger 52 moves to the left, half of the amount of oil sucked into the suction side gap 63, which is twice the amount of oil in the discharge side gap 61, is discharged through this discharge path before the plunger 52 moves to the right and stops. ,
The remaining half is left in the discharge side gap 61 when the plunger 52 stops. Half of the amount of suction oil remaining in the discharge side gap 61 will be discharged when the plunger 52 moves to the left again. Therefore, this hydraulic pump has plunger 5.
When the oil pump 2 moves left and right, half of the amount of oil it takes in is discharged.

The cross-sectional area of pressurization applied to the plunger 52 when the plunger 52 moves left and right is the difference in cross-sectional area between the piston portion 58 and the plunger 52 when the plunger 52 moves to the left, and conversely, when the plunger 52 moves to the right This is the difference in cross-sectional area between the plunger 52 and the suction oil amount limiting rod 67, and since these two cross-sectional area differences are equal, the load applied to the air drive device is always constant.

As described above, in the present invention, the signal pressure outlet hole 26 is provided in the guide cylinder 17, and the distance from the signal pressure outlet hole 26 to the spool valve is short.
Problems such as (1), (2), and (3) above do not arise. Also, since the supply and exhaust passage to the left cylinder chamber 15 is provided within the rod 13 of the driving piston 12,
Problems like (4), (5), and (6) above do not occur.

In addition, when conventional spool valves were switched using only air, the structure became complicated, and therefore the repulsive force of a compression spring was used for movement in one direction, but with the present invention, switching is possible using only air. It has a simple structure. Moreover, unlike conventional air valves, there is no need to provide a pilot valve that utilizes a compression spring and the mechanical pressing force of the driving piston in a part of the air valve passage, so the driving piston can operate at high speed.

Furthermore, the pressurizing cross-sectional area of the hydraulic pump is the piston portion 5
8 and the plunger 52, and between the plunger 52 and the suction oil amount limiting rod 67.In order to reduce the pressurizing cross-sectional area, there is no need to reduce the diameter of the plunger as in the conventional case. By considering the cross-sectional area of the suction oil amount limiting rod 67, the cross-sectional area can be set to any desired value. Further, by appropriately selecting the above-mentioned differences in cross-sectional area, the pressurized cross-sectional area can be made small, so that even an air drive device with limited horsepower can easily drive the pressurizing cross-sectional area.

In addition, as an example, the spool valve, its operating mechanism, and the hydraulic pump are both connected to the drive cylinder 1.
1, but it is also possible to separately provide each on both sides of the drive cylinder 11. For example, as shown in FIG.
The inner hole 14 and the left cylinder 15 may be communicated with each other by making a hole 72.

[Brief explanation of the drawing]

1 to 5 show a first embodiment of the present invention, FIG. 1 is a longitudinal sectional view, and FIG. 2 is a longitudinal sectional view of FIG. The state after moving for half a cycle is shown.
Also, Fig. 3 is a partial vertical cross-sectional view of Fig. 1-, and Fig. 4 is a cross-sectional view of Fig. 1-.
Figure 3 shows the spool valve after it has moved half a cycle relative to Figure 3; FIG. 5 is a cross-sectional view of FIG. 1. FIG. 6 is a partial side view of the section shown in FIG. FIG. 7 is a partial vertical sectional view of a second embodiment of the invention. 11... Drive cylinder, 12... Drive piston, 13... Rod, 14... Hole, 15... Left cylinder chamber, 16... Spool valve control guide, 17...
Guide cylinder, 18... Air passage, 19... Separation wall, 20... Right cylinder chamber, 21... Wall, 2
2... Air passage chamber, 23... Hole, 24... Bolt, 2
5... Separation wall, 26... Signal pressure extraction hole, 27... Signal pressure discharge hole, 28... Hole, 29... Hole, 30... Spool,
31... Sleeve, 32... First support cylinder, 33... Seal plate, 34... Hole, 35... Groove, 36... Mounting member,
37...Second support cylinder, 38...Protrusion, 39...Hole,
40...hole, 41...air supply pipe, 42...hole, 43
...hole, 44...groove, 45...groove, 46...first supply/exhaust hole, 47...second supply/exhaust hole, 48...exhaust hole, 49
...exhaust hole, 50...muffling chamber, 51...muffling chamber, 52...
Plunger, 53... Seal wall, 54... Cylinder block, 55... Mounting plate, 56... Bolt, 57
... Bore, 58 ... Piston part, 59 ... First check valve, 60 ... Hole, 61 ... Discharge side gap, 62
... Hole, 63... Suction side gap, 64... Suction port, 65...
Hydraulic pipe, 66...second check valve, 67...suction oil amount limiting rod, 68...discharge path, 69...discharge port, 70...discharge path, 71...third check valve, 72...hole.

Claims (1)

[Scope of Claims] 1. One cylinder chamber of the drive cylinder and the spool valve are communicated with each other by a first air passageway, which is a hollow hole provided in the drive piston rod, and the other cylinder chamber is communicated with the spool valve. and the spool valve are communicated through a second air passage,
Further, each end face of the spool of the spool valve is provided with an air supply hole and a blind hole having a larger cross-sectional area than the air supply hole, and the blind hole and the air supply hole are each provided with a first fixed hole. The hollow support cylinder and the second hollow support cylinder are fitted so as to slide inside the hole, and the space between the hollow hole of the first air passage and the spool valve is the other cylinder chamber of the drive cylinder. A guide cylinder having a diameter larger than the drive piston rod is provided concentrically outside the cylinder, and the drive piston rod is extended inside the cylinder, and the end of the hollow hole is opened in the extended portion, and a guide cylinder is provided for driving the guide cylinder. The cylinder side is communicated with the spool valve, so that both the hollow hole and the spool valve are communicated with each other, and there is also a guide on the side away from the opening end of the hollow hole with respect to the driving cylinder of the driving piston rod. A spool valve control guide that slides inside the cylinder is fixed, and furthermore, a signal pressure take-off hole is provided in the middle of the guide cylinder, which communicates with the hollow hole of the first hollow support cylinder through a sealed path. An air drive device is provided with a signal pressure discharge hole on the side remote from the signal pressure output hole with respect to the drive cylinder, and a piston portion that slides in a bore hole is provided in a part of the plunger driven by the drive piston rod. A suction oil amount limiting rod having a cross-sectional area smaller than the cross-sectional area of the plunger is provided in the opposite direction of the piston portion from the plunger, and the difference in cross-sectional area between the suction oil amount limiting rod and the piston portion is The cross-sectional area difference between the plunger and the piston is twice the difference in cross-sectional area between the plunger and the piston, and a flow path is provided inside the piston that communicates chambers on both sides of the bore partitioned by the piston. is an air-driven double-acting hydraulic pump equipped with a plunger-type hydraulic pump that is equipped with a check valve that allows the flow of oil only from the chamber on the plunger side to the chamber on the plunger side that limits the amount of suction oil; 2. The air-driven double actuator according to claim 1, wherein the cross-sectional area of the signal pressure discharge hole is made small so that the intake air from the signal pressure discharge hole is restricted as the spool valve control guide moves. type hydraulic pump.