JPH0410532Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) This invention relates to an electric expansion valve.

(Prior Art) As a conventional example of an electric expansion valve used in a refrigeration system, there can be mentioned, for example, an expansion valve described in Japanese Utility Model Application Publication No. 182577/1983. This electric expansion valve is shown in FIG. 3. In the figure, 51 is a valve body, and this valve body 51 has a first passage 52 opened at the side and a second passage 53 opened at the end.
are provided for each. The first passage 52 and the second passage 53 communicate with each other via a passage 54, and a valve seat 55 is formed within this passage 54. On the other hand, the back of the valve body 51 is hermetically covered by a case 56, and a coil 57 is disposed on the outer periphery of the case 56, and a rotor 58 is disposed inside the case 56.
A permanent magnet 59 is attached to the outer periphery of the magnet. That is, by inputting an electrical input such as a pulse to the coil 57, the rotor 58 can be driven to rotate. On the other hand, a cylindrical fixed bearing 60 is attached to the center of the upper end of the valve body 51, and the rotor 5 is attached to this fixed bearing 60.
A cylindrical propulsion bearing 61 fixed to the inner peripheral surface of 8 is screwed. The valve body 63, which is pressed and urged downward by the spring 62,
The valve body 63 is disposed at the axial center position of the valve body 63 through the fixed bearing 60, and a valve portion 64 is integrally formed at the tip of the valve body 63. Therefore, the rotor 58
is rotationally driven, this rotor 58 simultaneously moves linearly in the axial direction, and furthermore, the valve body 63
is also moved in the axial direction, the opening degree between the valve portion 64 and the valve seat 55 is adjusted, and the amount of refrigerant flowing from the first passage 52 to the second passage 53 is adjusted.

On the other hand, a pin 65 is erected on the upper end surface of the rotor 58 at a position away from its axis. A mandrel 66 is fixed to the case 56 on the central axis of the rotor 58, and a helical guide ring 67 made of an elastic metal wire is wound around the mandrel 66. Furthermore, a slider 68 is provided which is wrapped around the spiral groove of the spiral guide ring 67 and is rotatable and movable in the axial direction. This slider 68 has a contact piece 6 extending in the radial direction so as to be able to contact the pin 65.
9 is formed.

The mechanism made up of these parts is for determining the stopping position of the rotor 58. That is, when the valve is opened, the rotor 58 rotates and moves upward, but at this time the slider 68 is moved upward by the contact piece 6.
Pin 65 erected on rotor 58 via pin 9
and thus the helical guide ring 6
It rises guided by the spiral groove 7. and,
When the slider 68 reaches the upper end of the spiral guide ring 67, the movement of the slider 68 is restricted there, and conversely, the rotation and linear movement of the rotor 58 are stopped by the contact piece 69 and the pin 65. That's what happens. Further, even when the valve is closed, the movement of the slider 68 is restricted by the lower end of the spiral guide ring 67, and the rotor 58 is similarly stopped.

In this way, by providing a stopping mechanism for the rotor 58, there is an advantage that a large torque is not required even when the valve is opened, and therefore the electric drive mechanism consisting of the coil 57 and the permanent magnet 59 can be made small. . That is, the valve portion 64 comes into contact with the valve seat 55,
Even after the valve is in the closed state, the electrical drive mechanism continues to input the closed state signal, but the rotational torque applied to the rotor 58 at this time is the same as that without the above-mentioned stopping mechanism. , it continues to act as a tightening force on the valve body 63.
Therefore, when opening the valve, in addition to a force to overcome the differential pressure across the valve portion 64, a force to release the tightened state is required.

(Problem to be solved by the invention) By the way, in the electric expansion valve as mentioned above,
Since the pin 65 and the elastic slider 68 constitute a stopping mechanism, when the pin 65 stops in contact with the slider 68, the rotor 58 is largely repulsed by the spring force of the slider 68, causing it to move in the opposite direction. Rotation occurs. Also, the pin 65 is connected to the elastic slider 68.
When the rotor 5 is stopped due to the magnetic repulsion while the pulse is in the same direction, the rotor 5
8 moves in the opposite direction by one step angle and returns to its original position, causing rotational vibration. Therefore, the collision and repulsion between the pin 65 and the slider 68 are repeated, so the collision noise at this time is loud. There is a drawback. Furthermore, since the rebound movement in the opposite direction is large, there is also the drawback that the bearing portion is subject to large wear.
Furthermore, the slider 6 is inserted between the spiral guide rings 67.
8 slides, there is a large rattling, and there is also the problem that the sliding sound is audible to the outside through the thin case.

This invention was made in order to solve the above-mentioned conventional drawbacks, and its purpose is to reduce the stopper impact noise and rebound with respect to the rotation stop mechanism of an expansion valve driven by a pulse motor etc. An object of the present invention is to provide an electric expansion valve.

(Means for Solving the Problems) Therefore, in the electric expansion valve of this invention, an engagement recess 15 with a non-circular cross section that extends in the axial direction to the rear end face is bored in the axial center of the rotor 9, On the other hand, the valve body 1
A stopper bearing 24 is attached to the case 6 that covers the back of the
A stopper 25 that moves in the axial direction while engaging with the
Abutment members 26 and 27 are provided to which the stopper 25 is screwed and define the axially movable end of the stopper 25. A gap larger than the unit rotational displacement amount of 9 is provided.

(Function) As mentioned above, the stopper 25 is configured to move by screw feeding, so the sliding noise is small, and even when stopped, there is no spring reaction force unlike the conventional example, so the rebound movement is small and collisions occur. The sound can also be reduced. Furthermore, since the gap between the stopper 25 and the engagement recess 15 is formed to be larger than the unit rotational displacement of the rotor 9, the stopper 25 remains engaged even during rotational vibration of the rotor 9 within one step angle caused by magnetic repulsion when stopped. Since it does not hit anything other than the wall surface with which it was at least initially in contact within the mating recess 15, it is possible to construct an electric expansion valve with low noise.

(Example) Next, a specific example of the electric expansion valve of this invention will be described in detail with reference to the drawings.

In Fig. 1, 1 indicates the valve body,
This valve body 1 includes a first passage 2 that opens on the side.
and a second passage 3 that is open to the lower end. Both passages 2 and 3 communicate with each other via a passage 4, and a valve seat 5 is provided in this passage 4.
is formed. Further, the back part of the valve body 1, that is, the upper part in the figure, is hermetically covered by a case 6, and this case 6 includes a cap 7 attached to its upper end. A coil 8 is arranged on the outer periphery of the case 6, and a rotor 9 is arranged inside the case 6. Reference numeral 10 denotes a coil fixing plate. The coil fixing plate 10 has an upper bent portion attached to the cap 7 via a screw 11, and a lower bent portion to prevent the coil 8 from coming off. It is holding down the top surface. Note that the lower end of the coil 8 is supported by the outer periphery of the upper end of the valve body 1. A permanent magnet 12 is attached to the outer periphery of the rotor 9, and the permanent magnet 12 and the coil 8 constitute an electric drive mechanism 13 for rotationally driving the rotor 9. That is, by inputting an electrical input such as a pulse to the coil 8, the rotor 9 can be driven to rotate. In the axial center of the rotor 9, there is a recessed hole 14 having a circular diameter that extends in the axial direction and opens at the front end surface (lower end surface in the drawing).
An engagement recess, that is, a guide groove 15, extending in the axial direction to the rear end surface (upper end surface in the drawing) is formed.

On the other hand, a cylindrical fixed bearing 16 is installed at the center of the upper end of the valve body 1.
6, a cylindrical propulsion bearing 17 fixed to the inner peripheral surface of the recessed hole 14 is screwed. 18 is a ring-shaped spring receiver, and this spring receiver 18 is fixed between the upper end surface of the propulsion bearing 17 and the bottom surface of the recessed hole 14. A valve body 19 for opening and closing the flow path 4 through the spring bearing 18 and the fixed bearing 16 is disposed so as to be freely protrusive and retractable, and a valve portion 20 is formed at the tip of the valve body 19.
An upper washer 21 is attached to the upper end of the valve body 19 to prevent the valve body from coming off. Further, a stepped portion 22 is formed in the middle of the valve body 19, and a spring 23 is interposed between this stepped portion 22 and the spring receiver 18. The valve body 19 is pressed and urged downward by the spring 23 in the valve closing direction.

On the other hand, a stopper bearing 24 extending downward is attached to the cap 7.
is inserted into the center of the guide groove 15.
A stopper 25 is disposed within the guide groove 15 so as to be movable in the vertical direction, and the stopper 25 is screwed onto the stopper bearing 24. For this stopper 25, as shown in FIG. 2, the groove width d of the guide groove 15 is, for example, as shown in FIG. The dimensions are such that even if the rotor 9 rotates counterclockwise by one step θ while in contact with the corner y, a gap still remains between the other corner y and the other wall surface 15b. . Therefore, even if the rotor 9 undergoes rotational vibration with a displacement of one step angle θ, the stopper 25
There is no possibility that the stopper 25 itself will cause abnormal vibration due to repeated collisions with both walls.

On the other hand, abutment members 26 and 27 are attached to both upper and lower ends of the stopper bearing 24, as shown in FIG. These abutting members 26 and 27 are shock absorbers 28 and 29 made of an elastic material such as resin, respectively.
and shock absorber receivers 30 and 31, which define the axially movable end of the stopper 25. That is, when the rotor 9 rotates and descends to guide the valve body 19 in the valve closing direction, the lower end surface of the stopper 25 abuts against the buffer body 29 of the lower contact member 27, causing the lower end surface of the rotor 9 to When the rotor 9 rotates and ascends in order to restrict the above descent and guide the valve body 19 in the valve opening direction, the upper end surface of the stopper 25 comes into contact with the buffer body 28 of the upper abutment member 26. This makes it possible to prevent the valve body 19 from rising any further. Also, even when the stopper 25 contacts the upper contact member 26 in this way,
so that the upper end surface of the rotor 9, which has risen while rotating, is positioned above the upper abutting member 26.
The axial length of the guide groove 15, the lead of the threaded portion of the propulsion bearing 17, the lead of the threaded portion of the stopper bearing 24, and the mounting position of the abutting member 26 are selected. Therefore, the stopper 25 is always
Since the stopper 25 is located inside, the impact noise generated by the stopper 25 is mitigated and transmitted to the outside, resulting in a structure with less noise.

The rotor 9 and the stopper 25 are such that when the rotor 9 is lowered, the valve portion 20 of the valve body 19 first contacts the valve seat 5, and then a predetermined distance is applied to the force of the spring 23. A positional relationship is selected such that the stopper 25 comes into contact with the lower abutment member 27 when the rotor 9 is lowered.

Furthermore, the lead of the threaded portion of the stopper bearing 24 is set to a larger lead than the threaded portion of the propulsion bearing 17 so that the stopper bearing 24 is not tightened by the stopper 25 when the stopper 25 is stopped.

In the electric expansion valve described above, by inputting an electrical input such as a pulse to the coil 8, the propulsion bearing 17 rotates together with the rotor 9. Since this propulsion bearing 17 is guided by the fixed bearing 16, it is driven in the axial direction by the above rotation, and as a result, the valve portion 20 of the valve body 19 approaches and separates from the valve seat 5. It turns out. By adjusting the opening degree between the two passages 20 and 5, the amount of refrigerant flowing between the first passage 2 and the second passage 3 is adjusted.

In the electric expansion valve described above, when the rotor 9 is lowered when the valve is closed, the valve body 19 first
When the valve part 20 contacts the valve seat 5 and the rotor 9 further descends by a predetermined distance, the stopper 2
The lower end surface of the rotor 5 contacts the lower contact member 27, and the lowering of the rotor 9 is stopped. In this state, the valve body 19
is brought into contact with the valve seat 5 by the force of the spring 23. With this structure, a further pulse is input after the valve is closed, and due to the change in the magnetic pole position of the coil 8 and the repulsion of the magnetic pole of the permanent magnet 12 of the rotor 9, the rotor 9, the propulsion bearing 17 fixed thereto, and Even if a phenomenon occurs in which the spring receiver 18 moves back and forth repeatedly, this phenomenon is not transmitted to the valve body, and a stable valve closing state is obtained by the spring 23. On the other hand, at this time, the rotor 9 moves in the opposite direction by one step angle due to the magnetic repulsion and is returned to its original position, causing rotational vibration. Due to the gap provided, the stopper 25 can be attached to both wall surfaces 15 of the guide groove 15.
Since there is no repeated collision between a and 15b, no extra collision sound is generated. Moreover, since this position is inside the rotor 9, the sound heard outside is also small.

Further, when the valve is closed, when the rotor 9 is raised, the valve body 19 is
As the valve part 20 moves away from the valve seat 5 and the rotor 9 is further raised, the opening degree of the valve part 20 and the valve seat 5 becomes fully open, and at this time, the upper end surface of the rotor 9 is It is located above the contact member 26. Thereafter, the upper end surface of the stopper 25 comes into contact with the upper abutting member 26, and the upward movement of the rotor 9 is stopped.
At this time, another pulse is input in the same way as above,
Even if rotational vibration of the rotor 9 occurs due to magnetic repulsion, the same effect as described above is provided.

As explained above, in the electric expansion valve of this invention, since no spring reaction force is applied to the collision part of the stopper 25, there is no repetition of large repulsion and reversal, and the durability of the bearing screw part is improved. Furthermore, since a gap corresponding to one step angle or more is provided between the guide groove 15 and the stopper 25, no abnormal vibration occurs even when continuous pulses are input. Furthermore, since the contact is made inside the rotor 9, the noise heard outside is also small. Furthermore, since the stopper 25 is moved by a feed screw, the sliding noise is small.

Furthermore, in the above embodiment, the movement pitch of the stopper 25 per rotor rotation is made larger than the movement pitch of the valve body 19, so that the phenomenon in which the stopper 25 is tightened by the stopper bearing 24 when the stopper 25 is stopped is prevented. Therefore, the force required to open the valve becomes smaller, and the electric drive mechanism 13 can be made smaller. Further, since both sides of the rotor 9 are supported by the propulsion bearing 17 and the stopper bearing 24, the rotor 9 may oscillate laterally between the fixed bearing 16 and the propulsion bearing 17, and between the stopper bearing 24 and the stopper 25.
There is no possibility that noise will be generated at each threaded portion in between. Further, since the stopper 25 abuts against the buffer materials 28 and 29 at the end of its axial movement, the generated noise is also reduced.

In the above embodiment, the slit-shaped guide groove 15 is used as an example of the engagement recess, but the engagement recess is not limited to this, and may be rectangular or other polygon, and a stopper shape that matches the shape may be used. Any combination of shapes can be selected. Furthermore, as an example of a mechanism that uses the fixed bearing 16 and the propulsion bearing 17 as a mechanism for converting the rotational movement of the rotor 9 into a linear movement of the valve body 19, the mechanism is not limited to this, and in short, any mechanism that can perform this function Any mechanism may be used. Further, the inner peripheral surface portion of the guide groove 15 of the rotor 9 is connected to the stopper 2.
In order to improve the movement of 5, it may be constructed separately from resin or the like.

(Effects of the invention) In the electric expansion valve of this invention, the rotor is provided with an engagement recess that engages with the stopper, and the gap between the stopper and the guide groove is enlarged.
Since the stopper is configured to be screw-fed, compared to the conventional example in which the stop mechanism is configured with a pin and an elastic slider, the rebound at the time of a collision can be reduced, and the durability of the bearing can be improved. Furthermore, the impact noise and sliding noise of the stopper can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electric expansion valve according to an embodiment of the invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a sectional view of a conventional electric expansion valve. 1... Valve body, 2... First passage, 3... Second passage, 4... Flow path, 5... Valve seat, 6... Case, 9
... Rotor, 13 ... Electric drive mechanism, 15 ...
Guide groove (engaging recess), 19... Valve body, 24...
Stopper bearing, 25... Stopper, 26, 27...
...Abutment member.

Claims (1)

[Scope of utility model registration request] A valve seat 5 is provided in a flow path 4 that communicates between a first passage 2 and a second passage 3 provided in the valve body 1, and the above-mentioned In an electric expansion valve provided with a valve body 19 that is driven in the direction of contacting and separating from the valve seat 5,
An engagement recess 15 having a non-circular cross section is formed in the axial center of the rotor 9 and extends in the axial direction to the rear end surface, and a stopper bearing 24 is attached to the case 6 that covers the back of the valve body 1. A stopper 25 that engages with the engagement recess 15 and moves in the axial direction is screwed onto the stopper bearing 24, and abutting members 26 and 27 are provided to define the axially movable end of the stopper 25. An electric expansion valve characterized in that a gap larger than the unit rotational displacement of the rotor 9 by the electric drive mechanism 13 is provided between the stopper 25 and the engagement recess 15.