JPS5825181B2 - cam mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam mechanism that converts rotational motion into reciprocating motion.

Conventionally, as cam mechanisms for converting rotational motion into linear reciprocating motion, there have been two types: one in which a reciprocating body directly contacts a cam surface protruding from a rotating shaft, and the other in which a crank mechanism is used.

In the former case, where the reciprocating body is in direct contact with the cam surface, there is severe wear on the contact surface, and the cam and the reciprocating body cannot be connected, and the return movement of the reciprocating body is carried out by an elastic body such as a spring. There was a problem with followability.

In addition, with the latter crank system, there is no reciprocating motion (the double interlocking body is forced to move, but the large end of the connecting rod performs circular motion, resulting in large rocking motion, making it difficult to maintain dynamic balance. Additionally, a connecting rod had to be interposed between the reciprocating body and the crankshaft.

Therefore, the present invention was devised in view of the above problems, and provides a cam mechanism that has good followability and can convert rotational motion into reciprocating motion without large swinging. The purpose is to

Therefore, the feature is that an eccentric cam with a circular cross section having an axis parallel to the coaxial center is provided on the rotating shaft, a guide member is fitted on the outside of the cam so as to be relatively rotatable, and the guide member has a radially movable mechanism. The rotary shaft is unrotatably connected to the fixed member via the rotary shaft, and is also operatively connected to a reciprocating body disposed in the radial direction of the rotating shaft.

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

In FIGS. 1 and 2, reference numeral 1 indicates a hydraulic pump employing the cam mechanism of the present invention, for example, a hydraulic pump.

Reference numeral 2 designates a pump casing of the hydraulic pump, which includes an inside cover 5 from which a spline end 4 of an input shaft 3, which is a rotating shaft, protrudes, and a bolt 6 from the right side of FIG. The input shaft 3 consists of an outside cover 7 that is fixed to the inside cover 5.
Bearing 9゜1 fitted in bearing case part 8 of
0, is rotatably supported on the inside cover 5,
The input shaft 3 is interlocked with the braked rotary shaft 11 at the spline end 4 so as to rotate integrally therewith.

This connection can be made freely by using a key, a coupling, etc., but it is also possible to make the braked rotating shaft 11 and the input shaft 3 integral to achieve compactness.

The braked rotating shaft 11 is a front axle, a rear axle, or the like of the vehicle.
Alternatively, the drive shaft thereof may be a rotary shaft within the transmission case, and the hydraulic brake device has many effects as described later, and is preferably used as a brake device for a vehicle.

Note that 12 is a bearing case cover, which is fitted with the manpower shaft 3 via a sealing material 13 to seal the inside of the casing 2, and is attached with bolts 14.

15 is a fixing member that fixes the pump casing 2;
In the illustrated example, a bolt hole 16 is provided in a part of the inside cover 5, and a port 17 is screwed into the bolt hole 16 to fix it. However, depending on the case, the outside cover 7 and the fixing member 15 can be fixed. , whereby the braked rotating shaft 11
Generates a reaction force when braking.

As is clear from FIG. 2, 18 is six cylinders arranged in the radial direction, and the guide member 1 to be described later.
The pump casing 2 is pivotally connected to the pump casing 2 by cylinder pins 20ζ parallel to the input shaft 3, and is swingable around the pins 20.

As is clear from FIG. 2, the cylinder pin 20
are arranged at equal intervals around the circumference, such as the axis of the input shaft 3.

One end 20a is tightly fitted into the through hole 21ζ of the disk-shaped outside cover 7, and the other end 20b is tightly fitted into the annular shaft 22.
The annular shaft 22 is tightly fitted into the through hole 23 of the pump casing 2, and the annular shaft 22 is also tightly fitted into the annular protrusion 24 of the inside cover 5, which is formed to protrude inside the pump casing 2.
0b is pivotally supported by the inside cover 5 via an annular shaft 22.

Reference numeral 25 denotes an oil passage formed from the end 20a in alignment with the axis of the pin 20, and communicates with an oil passage 26 formed in the radial direction near the axis of the cylinder 18.

Thus, the cylinder 18 slides in the axial direction on the inner circumferential surface 29 of the cylinder tube 28, which is in the shape of a cylindrical body with a garden, and which is pivotally connected to the cylinder pin 20 through the bushing 27. It is composed of a freely reciprocating body 30.

In the illustrated example, the reciprocating body 30 is composed of a piston 32 having a piston ring 31 and a piston rod 33, but the piston 32 may have only a labyrinth groove or a plunger may be used instead of the piston. Be free.

34 is a high pressure chamber, which is surrounded by the piston 32, the inner circumferential surface 29 of the cylinder tube 28, and the bottom 35 of the cylinder tube 28, and the high pressure chamber 34 includes:
An oil passage 36 formed in the bottom portion 35 and the bush 27
The core oil passage 36 is divided into two parts with a predetermined interval apart in the axial direction.
The annular oil passage 37 is formed at a position corresponding to the oil passage 26 and communicates with the oil passage 25 through two oil passages 36 and 37.

On the other hand, the end of the cylinder tube 28 opposite to the bottom 35 is open to the pump casing 2 .

Next, 38 is a cam mechanism according to the present invention that interlocks and connects the input shaft 3 and the reciprocating body 30, and the cam mechanism 38 has a function of converting the rotational movement of the input shaft 3 into the reciprocating movement of the cylinder 18. It has the following.

Next, to explain this cam mechanism 38, 39 is an eccentric cam fixed to the inner end 41 of the input shaft 3 via a key 40 so as to rotate integrally with the input shaft 3.
The eccentric cam 39 and the eccentric cam 39 may be integrally formed, or they may be fixed by other means such as splines.

The outer circumferential surface 39a of the eccentric cam 39 is a perfect circle, and the inner ring of the bearing 42 is tightly fitted onto the outer circumferential surface 39a.

Reference numeral 19 denotes a guide member rotatably fitted to the outer circumferential surface 39a via the bearing 42, and the guide member 19 is eccentrically connected to the inner end 41 of the input shaft 3 as shown in the figure. A surrounding fitting part 44 surrounding the cam 39 etc., and the reciprocating body 3
and a mounting portion 43 to which an end portion 45 of the 0 is pivotably attached.

That is, in the illustrated example, the guide member 19 of the piston rod 33
The side end portion 45 is formed in a continuous manner as a short cylindrical body having an axis perpendicular to the entire axis of the piston rod 33 .

The fitting recess 47 of the guide member 19 corresponding to this is a cylindrical groove having an axis parallel to the axis of the guide member 19, as can be seen from both FIGS. The end portion 45 can be inserted from the right side in FIG. 1 to the left.

Furthermore, the fitting recesses 47 having the cylindrical grooves are arranged at equal intervals on the circumference around the axis of the guide member 19.

In addition, even if a tensile force is applied to the reciprocating body 30, the end portion 45
is configured so that it cannot be pulled out from the fitting recess 47.

Reference numeral 48 denotes a non-rotatable but radially movable mechanism, the details of which are shown in FIG.
protruding strips 52 and 53 each having a rectangular cross section are provided in series in a row,
In addition, the protrusions 52 and 53 are arranged to be perpendicular to each other in the front view.

A concave groove 54 is provided on the end surface of the mounting portion 43 of the guide member 19, into which the protrusion 52 is slidably fitted, and
By similarly providing a concave groove 56 into which the convex groove 53 is slidably fitted at a corresponding position on the inner surface 55 of the outside cover 7, the guide member 19 cannot rotate with respect to the pump casing 2 and has a diameter. It is configured to be movable in the direction and its movement is restricted.

Note that the above-mentioned grooves and protrusions may be provided on either of the opposing surfaces, and the combination thereof is free.

In this way, the cam mechanism 38 includes the eccentric cam 39, the guide member 19, the radially movable mechanism 48, and the like.

As shown in FIGS. 1 to 3, the pump casing 2 is filled with a working liquid, and the tank 57
It is also used as.

If hydraulic oil is used as the working fluid, this hydraulic pump 1 will be called a hydraulic pump, but inside the pump casing 2 are the rolling parts of the bearings 9, 10, 42, and the end part 45, as described above. The sliding part between the and fitting recess 47, the sliding part between the protruding strips 52, 53 and the groove grooves 54, 56, the cylinder tube inner circumferential surface 29, the cylinder pin 20 and the bushing 27
Since it has many sliding parts such as sliding parts and rolling parts, it is extremely preferable from the viewpoint of lubrication.

Next, 58 is a check valve, and through this check valve 58, the working liquid is sucked into each cylinder 18 from the pump casing 2 which also serves as the tank 57.

In the illustrated example, the valve body 59, which is a prismatic body with a hexagonal outer cross section, includes a poppet and a spring (not shown) in the shape of a ball or cone, and the operating liquid is sucked in from the suction port 60.

The check valve 58 is fixed to the bottom 35 of the cylinder tube 28 with a screw or the like, communicates with the high pressure chamber 34 via the annular oil passage 37 and the oil passage 36, and is configured to be sucked into the cylinder 18. In addition, the valve body 59 has a thickness that does not interfere with the adjacent cylinder 18 or the inner surface of the casing 2 even if the cylinder 18 swings around the pin 20, and the mounting direction is also set accordingly.

Next, in FIGS. 1 and 3, 61 is a valve device, which is installed in the discharge side circuit 62 of the hydraulic pump 1 and controls the flow rate, pressure, etc. This is for applying a braking force to the control rotation shaft 11.

) In the example shown in FIG. 1, a valve block 64 containing check valves 63 is fixed to the right side of the outside cover 7 with bolts or the like (not shown), corresponding to the opening positions of the oil passages 25 of the individual cylinders 18. Further, the oil passage 65 in the block 64 joins the annular oil passage 66 in the outside cover 7, and after the joining, the operating liquid is sent to the valve device 61 by the discharge side circuit 62. It is composed of

Of course, unlike the illustrated example, this merging may be performed by piping, or the individual valve blocks 164 may be integrated and an oil passage corresponding to the annular oil passage 66 may be formed therein.

Note that the number of cylinders 18 can be increased or decreased arbitrarily, so the second
The figure shows a case of 6 lines, and FIG. 3 shows a case of 3 lines.

Thus, in FIG. 3, the valve device 61 includes an IJ valve 67 for controlling pressure and a switching valve 68 for controlling direction.

In other words, the IJ IJ valve 67 is connected to the discharge side circuit 6.
If the pressure of the oil rises above a certain level, the oil will flow back through the return oil passage 69 into the pump casing 21 that also serves as the tank 57.

In addition, a female screw hole 70 is provided in a part of the inside cover 5 forming the pump casing 2 in FIG. It will be done.

Further, the switching valve 68 is exemplified as a two-position manual switching valve that connects the discharge side circuit 62 and the return oil passage 69.

Furthermore, the spool has a shape that allows the flow of liquid to be gently restricted during switching between the two positions of disconnection and connection.

In the normal state, as shown in FIG. 3, the liquid that has been brought into contact by the spring 71 and has flowed through the discharge side circuit 62 returns to the tank 57 through the oil passage 69, and therefore flows into the high pressure chamber 34 of the cylinder 18. , no pressure is generated and the input shaft 3
rotates freely with almost no resistance, and the braked rotary shaft 11, which is interlocked and connected, is in a state of free rotation with no brake applied.

Next, to apply the brake, push the spool upward in the diagram with the manual lever 72. The spool gradually narrows the oil passage inside the valve 68, increasing the passage resistance, and increasing the oil passage inside the discharge side circuit 62. The pressure increases and therefore the pressure in the high pressure chamber 34 in the cylinder 18 increases, causing the reciprocating body 3
A braking force is applied to the input shaft 3 and, therefore, to the braked rotating shaft 11 via the above-described structure such as the cam mechanism 38.

If this spool switching is performed suddenly, the discharge side circuit 62
The internal pressure suddenly rose, and the IJ IJ-F valve 67 caused the
If the pressure exceeds a predetermined value, damage to each component of the hydraulic pump 1, the braked rotating shaft 11, etc. is prevented.

In the disconnected state where the spool is pushed completely upward ζ, a predetermined pressure is maintained in the discharge side circuit 62 by the IJ IJ-F valve 67 and the oil is returned from the oil passage 69 to the tank 57.
Reflux to.

Next, FIG. 4 shows a case where a variable flow rate adjustment valve 73 for steplessly controlling the flow rate is installed as the valve device 61, and when the above-mentioned hydraulic brake device is used in a vehicle, etc. If the foot pedal 74 is depressed in the direction of the arrow so that the adjustment can be made easily and quickly, the valve 73 is gradually throttled and the pressure inside the discharge side circuit 62 increases, resulting in the same effect as described above. A braking force will be applied to the shaft 3.

It should be noted that the foot pedal 74 and the valve 73 are interlocked as shown by the imaginary line in the figure, but specifically, the foot pedal 74 and the valve 73 are interlocked and connected to each other by a rod, a control wire, etc.

In addition, as described above, the IJ IJ-F valve 67 is connected to the valve device 61 in order to prevent damage to the components of the hydraulic pump 1.
The working fluid returns from the oil passage 69 to the tank 57.
It is designed to flow back into the water.

In addition, this foot pedal 74 is connected to the switching valve 68 shown in FIG.
It is free to use the manual lever 72 as the variable flow rate adjustment valve 73.

Furthermore, it is also possible to control these valves 68, 73 by other signal transmission mechanisms such as solenoids or air cylinders.

As described above, since the hydraulic brake device employing the cam mechanism 38 of the present invention controls the operating fluid by the valve device 61, there is no shock or noise during braking,
When used in various vehicles such as automobiles, construction vehicles, agricultural vehicles, etc., it becomes an extremely excellent braking device. Therefore, it is preferable to select the front axle or rear axle of the vehicle as the rotating shaft 11 to be braked, or the drive shaft of the vehicle. It is preferable to select

Further, the hydraulic brake device includes a plurality of cylinders 18 having reciprocating bodies 30 disposed in the radial direction in the pump casing 2, and a cylinder tube 28 of the cylinder 18.
The input shaft 3 of the hydraulic pump 1 is pivotally connected to the pump casing 2 so as to be able to swing freely, and the input shaft 3 of the hydraulic pump 1 can be interlocked and connected to the rotary shaft 11 to be braked.
and the reciprocating body 30 are interlocked and connected via a cam mechanism 38, and a valve device 61 for controlling flow rate, pressure, etc. is interposed in the discharge side circuit 62 of the hydraulic pump 1. Because the cylinder 18 is fixed and does not rotate, there is little power loss when not braking, it has a long life, and there are few failures, and since it uses working fluid, there is no shock or noise when braking, and, Since the valve device 61 only brakes the pressure, flow rate, etc. on the discharge side of the hydraulic pump 1, a sufficiently large braking force can be obtained with a small operating force.

In addition, in the cam mechanism 384, the end portion 45 of the reciprocating body 30 is pivotally connected to the guide member 19, and a force is applied by the guide member 19 when forcing the working liquid in the direction of pulling it during suction. Even in the high-speed range of the brake shaft 11, the cylinder 1
8 can suck the working liquid from the suction port 60,
It can withstand high-speed use.

Note that this ease of suction becomes even more remarkable because the length of the suction oil path to the cylinder 18 is shortened by using the inside of the pump casing 2 as the tank 57.

Furthermore, if hydraulic oil is used as the working fluid, the hydraulic pump 1 becomes a hydraulic pump, which improves the lubricity of many sliding and rolling parts inside the pump casing 2 and extends its life, which is preferable. be.

Furthermore, according to the cam mechanism 38 of the above embodiment, the reciprocating body 3
0 is moved via the guide member 19 that does not rotate, so the end 45 of the moving body 30 and the fitting recess 4 of the guide member 19
7 and ζ have less wear due to friction, and the mounting part 43
Since the end of the piston rod 33 is connected to the outer periphery of the pump 1, a plurality of cylinders 18 in the circumferential direction can be arranged in the same plane, and the axial dimension of the pump 1 can be reduced compared to a crank mechanism. can be made compact.

As described in detail above, according to the cam mechanism of the present invention, the cam and the reciprocating body are interlocked and connected via the non-rotating guide member, so the followability is good, there is little wear due to friction, and there is no vibration. Since the dynamic movement is also reduced, vibrations and the like are also reduced, and it exhibits great effects in practical use.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of a hydraulic brake device showing an embodiment of the present invention, Fig. 2 is a front view of the same partly in section, Fig. 3 is an explanatory circuit diagram of the device, and Fig. 4 is a An explanatory circuit diagram showing another embodiment, FIG. 5 is a front view of a non-rotatable but radially movable mechanism. 1... Hydraulic pump, 2-... Pump casing, 3... Input shaft, 11... Braked rotating shaft, 18... Cylinder, 19...
・Guide member, 28...Cylinder tube, 30
...Reciprocating body, 38...Cam mechanism,
39-...Eccentric cam, 41...Inner end,
42...bearing, 45...end, 4
8...Non-rotatable and radially movable mechanism, 57
... Tank, 61 ... Valve device, 62
...Discharge side circuit.

Claims (1)

[Claims] 1 In a cam mechanism that converts rotational motion into reciprocating motion,
An eccentric cam with a circular cross section and an axis parallel to the coaxial center is fixed to the end of the rotating shaft, and a guide member is fitted around the cam so as to be relatively rotatable, and the guide member has a radially movable mechanism. is unrotatably connected to the fixed member via the
A reciprocating body disposed in the radial direction of the rotating shaft is rotatably connected to the guide member, and the radially movable mechanism is configured such that the end face of the guide member covering the end face of the rotating shaft faces the fixed member. It has a disc body between the faces, a groove or a convex groove is provided on the diameter of one end face of the disc body, and a concave groove or a convex line is provided on the diameter of the other end face in a direction perpendicular to the groove or convex line. A groove or a convex groove is provided, and a convex groove or a concave groove that slidably fits into the groove or convex groove is provided on the diameter of the end surface of the guide member and on the opposing surface of the fixed member, respectively. A cam mechanism characterized by: